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hunterseeker5

R-hop installation manual (Necro Exempt)

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<AT> buppus

 

- The chopstick is one of those thinner ones you get from a restaurant - one of the disposable ones. I find they're about as wide with the sandpaper as the saw blade sharpener, but allow me to take that *tiny* bit off slowly, versus having to steady a multi-thousand RPM dremmel in my hand to take minimal amounts of material off.

 

Koolor, what barrels were you using? I've tried Matrix(please don't flame me, I got it for free) Madbull, and some stock barrels(Jg, ICS, E1) I've had and none fit right in, or nearly as easy as yours.

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I used a Prometheus 6.03 this was my first time doing this and it took me literally less then a half hour, it was such a nice drop in fit I honestly think I did it wrong but my results are proving me other wise lol. Anyway I might post my picture soonISH seeing even it if I did the install correctly but even if I did do it incorrectly im keeping it because I like my 400 foot dmr shots :a-cool:

Edited by Koolor

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I used a Prometheus 6.03 this was my first time doing this and it took me literally less then a half hour, it was such a nice drop in fit I honestly think I did it wrong but my results are proving me other wise lol. Anyway I might post my picture soonISH seeing even it if I did the install correctly but even if I did do it incorrectly im keeping it because I like my 400 foot dmr shots :a-cool:

 

 

You're a very good spokesman. I should get you to post about the R-hop EVERYWHERE. :P

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Ok so a while ago Krap101 posited the idea that something relatively "hard" which is active concave will, rather than producing even contact around a large part of the bb's circumference, only contact the bb along one point. Of course this is easy to shoot down because you'll notice every bb you fire, regardless of the hop type, comes out with a "smudge" on its surface finish which is visible. Of course this is very difficult to capture on camera, so I went ahead and coated a pearly white bb with black ink (I left the mold release film on it so the ink would come off quite easily) and fired it down a clean barrel. Gun was held vertical, and the bb was captured by a very soft backing. Subsequent shots were fired with un-treated rounds to insure the ink rub pattern was consistent with the standard contact pattern. The result was very difficult to capture, I don't know if it will appear well for you, but trust me its apparent if you examine the bb's reflection under light.

 

So now for pictures. Here are a few of the white bbs I used and the white bb post-treatment with ink.

425005_2893750056899_1054731304_2782187_128470371_n.jpg

 

Here is the image of the white bb showing where the ink has been scuffed off. Note the unusual ridging pattern. I'm not entirely sure why that appears.

401404_2893756177052_1054731304_2782188_935543635_n.jpg

 

And here is an image showing the scuff pattern on a black bb (I could get it to show up better on a black bb than a white one):

425616_2893746736816_1054731304_2782186_49345891_n.jpg

 

And for those skeptics who think this pattern is created by something else it should be noted that length of stroke correlates with pad length, and that similar (but shorter) patterns can be produced with standard hops as well. Basically the point is you can vary marks like this depending on your hop type, and it can also be used as a diagnostic if you so desire. :) Just don't do it a lot because ink can build up and f*ck your system. :)

Edited by hunterseeker5

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Ok so a while ago Krap101 posited the idea that something relatively "hard" which is passive concave will, rather than producing even contact around a large part of the bb's circumference, only contact the bb along one point. Of course this is easy to shoot down because you'll notice every bb you fire, regardless of the hop type, comes out with a "smudge" on its surface finish which is visible. Of course this is very difficult to capture on camera, so I went ahead and coated a pearly white bb with black ink (I left the mold release film on it so the ink would come off quite easily) and fired it down a clean barrel. Gun was held vertical, and the bb was captured by a very soft backing. Subsequent shots were fired with un-treated rounds to insure the ink rub pattern was consistent with the standard contact pattern. The result was very difficult to capture, I don't know if it will appear well for you, but trust me its apparent if you examine the bb's reflection under light.

 

So now for pictures. Here are a few of the white bbs I used and the white bb post-treatment with ink.

425005_2893750056899_1054731304_2782187_128470371_n.jpg

 

Here is the image of the white bb showing where the ink has been scuffed off. Note the unusual ridging pattern. I'm not entirely sure why that appears.

401404_2893756177052_1054731304_2782188_935543635_n.jpg

 

And here is an image showing the scuff pattern on a black bb (I could get it to show up better on a black bb than a white one):

425616_2893746736816_1054731304_2782186_49345891_n.jpg

 

And for those skeptics who think this pattern is created by something else it should be noted that length of stroke correlates with pad length, and that similar (but shorter) patterns can be produced with standard hops as well. Basically the point is you can vary marks like this depending on your hop type, and it can also be used as a diagnostic if you so desire. :) Just don't do it a lot because ink can build up and f*ck your system. :)

 

If you want to use my "vocabulary", then a hard nub/bucking which is flat will only product a single point or line of contact ( would not consider this concave at all), and active/passive concave will both produce an area of contact, but the method by which this is achieved is different. I did not say that a hopup would produce a single line of contact, but I used the two extremes, one very rigid hopup versus one very soft (LRB versus one of my beta nubs for example) so that we could more easily compare harder and softer hopup setups. An easy way to test this (as well as jam your gun), would be to use a piece of hard plastic as your nub (thick enough to not flex), then use something like sorbothane. The ridges are produced because there is not perfect contact with the bb.

 

The unevenness of the ridges leads me to believe that this is likely caused by "skidding" or possibly flex in the bucking-nub pair (or both). I'm around 98% sure that if you used a thicker softer rubber, you'd see a reduction in the "ridging", which is the idea behind the passive concave, because it "absorbs" the impact of the bb to provide the concave, rather than be pushed away.

Edited by krap101

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If you want to use my "vocabulary", then a hard nub/bucking which is flat will only product a single point or line of contact ( would not consider this concave at all), and active/passive concave will both produce an area of contact, but the method by which this is achieved is different. I did not say that a hopup would produce a single line of contact, but I used the two extremes, one very rigid hopup versus one very soft (LRB versus one of my beta nubs for example) so that we could more easily compare harder and softer hopup setups. An easy way to test this (as well as jam your gun), would be to use a piece of hard plastic as your nub (thick enough to not flex), then use something like sorbothane. The ridges are produced because there is not perfect contact with the bb.

 

The unevenness of the ridges leads me to believe that this is likely caused by "skidding" or possibly flex in the bucking-nub pair (or both). I'm around 98% sure that if you used a thicker softer rubber, you'd see a reduction in the "ridging", which is the idea behind the passive concave, because it "absorbs" the impact of the bb to provide the concave, rather than be pushed away.

 

Actually I believe you posted this:

IMO, the only benefit of concavity is to increase the available hop to the bb, but with a permanent concave, especially one that has been "abraded", from what I've seen of the process of making the R-hop, the "finish" can't be very good. For the same reason people began rotating their buckings after shaving them because of the imperfect contact area. I know you are shooting metal bb's, but for "normal" weight bb's, conventional hopup provides enough spin for straight flight, so the improvements must be made in the hopup for "consistency" in areas sych as surface finish, uniformity, and pressure. The R-hop does decouple air seal and hopup, but at the same time, while at the same time decrease pressure (I.e. angular acceleration), but you are also losing the consistency and finish of a molded bucking.

 

More or less, I find a large concave (I believe the R-hop to be at something like 8mm or so, and contact "angle" of ~60 degrees) unnecessary, as most airsofters aren't shooting .88g steel or whatever you're shooting nowadays. The "passive" concave will achieve a 6mm concavity every time, but will likely have less than ~20 degrees of contact angle, but the amount of hop available is still relatively high, as the bb has to "roll through" providing both friction and a "normal force", creating the magnitude of the moment/torque/force to be larger than a permanent concave of similar material, but these comparisons are a bit difficult, as the two hopup methods use two different means of providing hop, and obviously the numbers for concavity will change for each individual R-hop, and the contact angle is likely not terribly accurate.

 

There were mechanical problems with the beta 1 nubs, and I should be hearing back soon about whether the changes solved the problem in the beta 2 with the dual-stage nub.

 

These aren't to scale, and don't take into account how much deformation, and were made in 5 minutes, but they might help illustrate the difference between active and passive concave. In reality, I think the R-hop would have a larger contact area.

 

Active Concave: Permanent concave

6432380465_9976ff8d9d_b.jpg

 

 

6432379861_2afdf29e70_b.jpg

Passive Concave: Concavity due to deformation

 

6432379163_38ee52e637_b.jpg

 

6432413151_a415af4db6_b.jpg

 

That is the last explanation you gave on the "advantages" of active concave. This test nicely disproves your theory by showing even contact occurring the length and width of the R-hop. You didn't say it would be an infinitely fine point of contact, but you are clearly suggesting that the width of contact is less than a passive concave system. Its also worth noting that this is a very shallow R-hop put in an unmodified chamber.

 

The ridging isn't apparent from looking at the R-hop, so clearly it can't be caused by unevenness in the hop itself. I actually have a small handfull of rounds I put through the gun after the test to clean it out. The first one out the barrel after the inked bb, pictured below, shows this same ridging pattern. Subsequent rounds show this pattern fading to an even smudge which try as I might I can't really capture an image of. I mean I can capture an image which shows the edge of the smudge, but it doesn't really show the breadth of it. Tried a video and that just reduces the resolution to the point of uselessness. Anyway the rest of the rounds are unsorted but they actually show a range of disappearance of the ridging pattern. Now if I fire I get zero ridging just an even smudge. Why? Well my theory is that the ridges are not aligned with the direction of travel but perpendicular to the direction of travel. They are caused by the ink contaminating the hop causing alternating slip-catch movement. Once the ink has been fully blown off the hop you go back to full smudge contact. (in essence perfect contact)

 

For other people to reference here is the discussion on concavity from which I pulled the above quote and figures: (the thread was split from another thread for the record, which is why it appears with no context)

http://www.airsoftforum.com/board/Concavit...5#entry18583835

Edited by hunterseeker5

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Actually I believe you posted this:

 

 

That is the last explanation you gave on the "advantages" of active concave. This test nicely disproves your theory by showing even contact occurring the length and width of the R-hop. You didn't say it would be an infinitely fine point of contact, but you are clearly suggesting that the width of contact is less than a passive concave system. Its also worth noting that this is a very shallow R-hop put in an unmodified chamber.

 

The ridging isn't apparent from looking at the R-hop, so clearly it can't be caused by unevenness in the hop itself. I actually have a small handfull of rounds I put through the gun after the test to clean it out. The first one out the barrel after the inked bb, pictured below, shows this same ridging pattern. Subsequent rounds show this pattern fading to an even smudge which try as I might I can't really capture an image of. I mean I can capture an image which shows the edge of the smudge, but it doesn't really show the breadth of it. Tried a video and that just reduces the resolution to the point of uselessness. Anyway the rest of the rounds are unsorted but they actually show a range of disappearance of the ridging pattern. Now if I fire I get zero ridging just an even smudge. Why? Well my theory is that the ridges are not aligned with the direction of travel but perpendicular to the direction of travel. They are caused by the ink contaminating the hop causing alternating slip-catch movement. Once the ink has been fully blown off the hop you go back to full smudge contact. (in essence perfect contact)

 

For other people to reference here is the discussion on concavity from which I pulled the above quote and figures: (the thread was split from another thread for the record, which is why it appears with no context)

http://www.airsoftforum.com/board/Concavit...5#entry18583835

 

Okay, let me explain the difference between what I said and what you thought I said. From that post you quoted from me, I was trying to establish that an active concave will provide more hopup potential from a purely frictional standpoint (quite a few times I mentioned that a flat hop would jam before being able to hop something like a .88, and then you'd go on about tearing, so on and so forth), so I don't believe I ever said that the passive concave provided more "contact arclength" compared to a "active" or permanent concave; however, what I know I said is that there is a "displacement force" involved with the compression of the rubber, which is most prevalent in soft rubbers, and that is where I said the passive concave was better (remember the walking through the snow analogy?).

 

I said in that thread that the pictures were purely to explain how it worked, and was not to scale, and you commented about this.

 

More or less, I find a large concave (I believe the R-hop to be at something like 8mm or so, and contact "angle" of ~60 degrees) unnecessary, as most airsofters aren't shooting .88g steel or whatever you're shooting nowadays. The "passive" concave will achieve a 6mm concavity every time, but will likely have less than ~20 degrees of contact angle, but the amount of hop available is still relatively high, as the bb has to "roll through" providing both friction and a "normal force", creating the magnitude of the moment/torque/force to be larger than a permanent concave of similar material, but these comparisons are a bit difficult, as the two hopup methods use two different means of providing hop, and obviously the numbers for concavity will change for each individual R-hop, and the contact angle is likely not terribly accurate.

 

Here, in the quote you posted, I explain how the passive concave has less contact area, but makes up for it with the "displacement force". The reason I did not cad the passive and active concaves to scale, was that I did not have the material properties of the two materials, so I could not estimate the actual compression for the passive concave, or the amount of "give" in the active concave, and I also assumed people would read the post with the pictures and not take them out of context.

 

These aren't to scale, and don't take into account how much deformation, and were made in 5 minutes, but they might help illustrate the difference between active and passive concave. In reality, I think the R-hop would have a larger contact area.

 

Finally I said that in the post you quoted.

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My point of the vocab, was that you were using passive and active incorrectly. Passive refers to a soft rubber which is initially flat and compresses to accommodate the bb as it goes past, and active concave is one that has a curve permanently set in the material.

 

Ok so you just repeated exactly what my understanding of active and passive concave are...... HA you caught a minor error of mine. I just corrected it. I meant active concave (the R-hop) whoops. ::) How many times do I have to tell you to listen to what I'm thinking not what I'm saying. :P

 

Anyway back on point.

 

Okay, let me explain the difference between what I said and what you thought I said. From that post you quoted from me, I was trying to establish that an active concave will provide more hopup potential from a purely frictional standpoint (quite a few times I mentioned that a flat hop would jam before being able to hop something like a .88, and then you'd go on about tearing, so on and so forth), so I don't believe I ever said that the passive concave provided more "contact arclength" compared to a "active" or permanent concave; however, what I know I said is that there is a "displacement force" involved with the compression of the rubber, which is most prevalent in soft rubbers, and that is where I said the passive concave was better (remember the walking through the snow analogy?).

 

Ok lets briefly step back from this to define something. When you are holding a rifle, stock facing you, barrel away from you, gun vertical as if being held you define the X axis as running across the gun from left to right, the Y axis as running up and down from the grip to the optic, and the Z-axis as the direction of the bore yes? So if we define "contact arclength" as being purely in the X and Y axes, ignoring contact in the Z-axis so ignoring length of contact and your "walking through snow analogy," you are saying that active concave (semi stiff permanent curve, the R-hop) has the capability to produce equal or greater arclength to the passive concave (flat hop with ultra-soft nub)? If you are then we are in agreement, and I simply misinterpreted you.

 

I'm trying to, in this instance, avoid including the Z-axis in this contact area discussion for two reasons. First currently we don't have a particularly effective way of measuring it. We can create models and theorise, but nothing that can really demonstrate it. Second because we can't quantify it we also can't compare or understand its effects between systems. Thats why I'm looking purely at "width" of contact or what I BELIEVE you're calling "contact arclength."

Edited by hunterseeker5

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Ok so you just repeated exactly what my understanding of active and passive concave are...... HA you caught a minor error of mine. I just corrected it. I meant active concave (the R-hop) whoops. ::) How many times do I have to tell you to listen to what I'm thinking not what I'm saying. :P

 

Anyway back on point.

 

 

 

Ok lets briefly step back from this to define something. When you are holding a rifle, stock facing you, barrel away from you, gun vertical as if being held you define the X axis as running across the gun from left to right, the Y axis as running up and down from the grip to the optic, and the Z-axis as the plane of the bore yes? So if we define "contact arclength" as being purely in the X and Y axes, ignoring contact in the Z-axis so ignoring length of contact and your "walking through snow analogy," you are saying that active concave (semi stiff permanent curve, the R-hop) has the capability to produce equal or greater arclength to the passive concave (flat hop with ultra-soft nub)? If you are then we are in agreement, and I simply misinterpreted you.

 

I'm trying to, in this instance, avoid including the Z-axis in this contact area discussion for two reasons. First currently we don't have a particularly effective way of measuring it. We can create models and theorise, but nothing that can really demonstrate it. Second because we can't quantify it we also can't compare or understand its effects between systems. Thats why I'm looking purely at "width" of contact or what I BELIEVE you're calling "contact arclength."

 

I've stopped calling it width and changed to arclength to be more precise in my descriptions, because the surface of contact is curved. I've also been using the word "compressible" to refer to to rubber, which is technically incorrect. Rubbers actually maintain more or less constant volume under compression (squeeze it one way it will bulge out the other), so I need to find a better word...squishy comes to mind...

 

It sort of depends on what I'm talking about. If we're talking about a grouping (2-d), then +Y is up, and +X is to the right. If we're talking about the hopup/barrel (3d), I define +Z as up, +X is to the right, and Y is down the barrel (sorry, this is what is most comfortable for me, and it follows the right hand rule).

 

In my axes, the contact arclength would be in the X-Z plane (vertical plane extending left and right). So, an active concave (R-hop) will have a larger "arclength of contact, but not necessarily a larger accumulated area of contact (explained below), totally depending on the material properties, but I think the passive concave has a larger area of contact. Then you have to look at pressure (pressure*area=your normal force, which will translate into friction when multiplied by the coefficient of friction). Here the R-hop wins hands down. It can provide a much larger pressure than any soft nub (compressibility reduces this, but also increases the area of contact) , which is why you can hop .88's, but I still think a soft contact (passive) will give a better quality of contact, since "adapts" to the shape of the bb as it goes by increasing contact area and providing the "displacement force", which I've been able to hop .40g bb's with.

 

Thought experiment: if we measure integrate contact as a function of time, in the extreme cases, you'll have an arclength of contact (mm, in my X-Z plane), so as the bb "rolls" through the bucking, you're going to accumulate surface area at the rate of area of contact*surface velocity (mm*m/s) or mm^2/s, whereas with a passive concave, you'll have a surface of contact, so (mm^2*mm/s), or mm^3/s. So basically the surface of contact will accumulate area much faster in a passive concave than a active one (obviously, but somewhere on the order of length^1.5 times faster), which I will call the "accumulated area of contact".

Edited by krap101

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I've stopped calling it width and changed to arclength to be more precise in my descriptions, because the surface of contact is curved. I've also been using the word "compressible" to refer to to rubber, which is technically incorrect. Rubbers actually maintain more or less constant volume under compression (squeeze it one way it will bulge out the other), so I need to find a better word...squishy comes to mind...

 

It sort of depends on what I'm talking about. If we're talking about a grouping (2-d), then +Y is up, and +X is to the right. If we're talking about the hopup/barrel (3d), I define +Z as up, +X is to the right, and Y is down the barrel (sorry, this is what is most comfortable for me, and it follows the right hand rule).

 

In my axes, the contact arclength would be in the X-Z plane (vertical plane extending left and right). So, an active concave (R-hop) will have a larger "arclength of contact, but not necessarily a larger accumulated area of contact (explained below), totally depending on the material properties, but I think the passive concave has a larger area of contact. Then you have to look at pressure (pressure*area=your normal force, which will translate into friction when multiplied by the coefficient of friction). Here the R-hop wins hands down. It can provide a much larger pressure than any soft nub (compressibility reduces this, but also increases the area of contact) , which is why you can hop .88's, but I still think a soft contact (passive) will give a better quality of contact, since "adapts" to the shape of the bb as it goes by increasing contact area and providing the "displacement force", which I've been able to hop .40g bb's with.

 

Thought experiment: if we measure integrate contact as a function of time, in the extreme cases, you'll have an arclength of contact (mm, in my X-Z plane), so as the bb "rolls" through the bucking, you're going to accumulate surface area at the rate of area of contact*surface velocity (mm*m/s) or mm^2/s, whereas with a passive concave, you'll have a surface of contact, so (mm^2*mm/s), or mm^3/s. So basically the surface of contact will accumulate area much faster in a passive concave than a active one (obviously, but somewhere on the order of length^1.5 times faster), which I will call the "accumulated area of contact".

 

I'm not asking you to agree with my axis designation, just understand the plane I'm referring to. :a-wink: Either way we're in agreement regarding arc length in our respective systems.

 

Now moving from two dimensions, arc length of contact, to four and get surface area of contact over a period of time you posit that the passive concave systems will provide more contact than the active concave systems. This goes back to your "walking through snow" analogy. I think we have a problem of comparison here because you've not tried my R-hop and I've not tried your (I know you have several generations, not entirely sure on the overarching nomenclature of them) passive concave "Krap hop" systems. You see the R-hop, when installed as I prefer to do it, is actually quite thin and remarkably stretchy. You're right though that the various "rubbers" we use don't compress. Its a big problem I had actually because when I was looking at building an extended nub for the R-hop and particularly the ER-hop I have no room for expansion. Even ultra soft materials were behaving as if they were much harder because they had no room for lateral expansion. My solution, as used on the M-nub system, is to use a foam rather than a "gel" or some other semi solid so I can have compression without lateral expansion. In my testing this markedly improves R-hop performance and allows you to increase visible barrel intrusion because the nub truly behaves as a "soft" nub as its able to deform with ease in situ. Some people have tested it in flat hop applications and been less than impressed, others were absolutely thrilled with the results. I honestly can't comment because I do extremely limited flat-hop testing. I suppose if you wanted to compare contact quantitatively between the two systems across 4 dimensions it would be very tempting to base it purely off length of intrusion, arc of contact, and quantity of intrusion across time. The problem with this is the inherent rigidity and and limited elasticity limit the amount of actual contact. As a result I image the contact being less like a bowling ball rolling through snow than it is a bowling ball rolling across a trampoline or if you prefer a planet sitting on a grid on the cover of a stereotypical physics 101 textbook. :a-wink: The rubber both ahead of and behind the sphere is lifted away from the projectile, and this is really material specific. It presents a prickly testing problem to figure out which will produce more contact. For now we can only speculate and have fun. :)

 

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Hey guys - So after my first attempts at installing these, I haven't gotten one yet to really work... I haven't been using proper tools, though.

 

One problem that I've really run into, however, is how to cut the legs. I've seen the method of putting the R-hop between tweezers and sticking that into a vice, but what I'm actually concerned is how low should the R-hop sit compared to the OD of the barrel.

If you look at picture four of the original post, you'll see that the R-hop sits higher than the OD of the barrel, is this how I should get my legs to be? Or should it look more like pic two, where the R-hop sits flush.

Also, what tools do you guys use to cut the R-hop's legs? I've been using a simple knife and a dremel to sand it completely flat.

And is there any problem using scissors to cut the R-hop to length?

 

Finally (stupid question alert :a-grin: ), I might have missed this, but if I'm using the R-hop w/ .25s, am I able to adjust to .28s? I wouldn't think so (especially w/ the M-nub because of it's softness).

 

Thanks for your time

Edited by conanime

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The OD of the barrel and the OD of the patch should be flush. If they are not, when you slide the barrel/bucking into the chamber, the chamber will push it down a bit, requiring more sanding of the inner part of the patch.

 

I use an Xacto knife to cut it both to length as well as trim the legs off. You can use scissors, but remember, once you take off too much material, you can't really put it back on. I lay the full patch in the window, mark a spot longer than the window, cut it there, check the fit/how much more needs to be removed, and slowly slice a little bit more of the length off until it fits in the window.

 

Yes, you can adjust the R-hop to use .28g even though you tuned it to .25g. I tuned one of mine to handle .20g, but it adjusts to lift .28g (and I assume it will do the same for .30g but haven't tried yet) and it performs just fine.

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Try sanding to height rather than cutting, most people don't have blades available which are sharp enough to accurately cut it.

 

You want it to sit flush with the outside of your barrel.

 

yes you can adjust for heavier bbs.

Thanks - and when I sand it, can I use a Dremel or should I use a file or sandpaper? I know I'm free to expirement, but what would you personally use (if you didn't have those knives of yours :) I can't imagine sanding the legs down with 400 Grit sandpaper or files...

 

Also, when I look down a barrel with a properly installed R-hop, should the R-hop as low as the R-hop in pic 2? I ask because as I sand my CP down, I find that they end up being a lot higher (closer to the top of the barrel) than the one in pic 2.

 

Another thing I notice in my install is that when I look down the barrel w/ my R-hop in the window, the R-hop is not as indented as the one in pic 2. Essentially, my R-hop patch's sides start at the sides of the barrel window, whereas the sides of the R-hop patch in pic 2 has sides that are indented into the barrel. (I attached crudely drawn image to help you understand what I mean). Basically I wanted to know if when I look down a barrel with a properly installed R-hop, should it look like pic two, where the sides of the R-hop are dropped into the barrel, or can it look like mine, where the sides of the patch are flush with the ID of the inner barrel...

post-66059-1328683023_thumb.png

 

Also, if it is important, I am using .28s & my barrel window is about 1-2 mm deep from the inner diameter of the barrel. My gun shoots ~ 390 FPS.

 

Thanks again :)

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I don't do it a lot, but I have set R-hops to not even lift .12 and then lifted .43s with them. There is a huge range of adjustment available. ;) I still recommend the ER-hop for people shooting exclusively .3s and up.

Do you use the M-nub w/ yours? Because I find that due to the M-nub's softness, my hop doesn't actually adjust to much; rather, the M-nub just becomes squished as I turn the hop-up dial towards maximum.

 

I suppose, however, as long as I have my R-hop tuned for the BB I know I'm going to be using (.28), then I don't really mind not being able to adjust. I just have to use that same BB weight to get consistent hop.

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Thanks - and when I sand it, can I use a Dremel or should I use a file or sandpaper? I know I'm free to expirement, but what would you personally use (if you didn't have those knives of yours :) I can't imagine sanding the legs down with 400 Grit sandpaper or files...

 

Also, when I look down a barrel with a properly installed R-hop, should the R-hop as low as the R-hop in pic 2? I ask because as I sand my CP down, I find that they end up being a lot higher (closer to the top of the barrel) than the one in pic 2.

 

Another thing I notice in my install is that when I look down the barrel w/ my R-hop in the window, the R-hop is not as indented as the one in pic 2. Essentially, my R-hop patch's sides start at the sides of the barrel window, whereas the sides of the R-hop patch in pic 2 has sides that are indented into the barrel. (I attached crudely drawn image to help you understand what I mean). Basically I wanted to know if when I look down a barrel with a properly installed R-hop, should it look like pic two, where the sides of the R-hop are dropped into the barrel, or can it look like mine, where the sides of the patch are flush with the ID of the inner barrel...

post-66059-1328683023_thumb.png

 

Also, if it is important, I am using .28s & my barrel window is about 1-2 mm deep from the inner diameter of the barrel. My gun shoots ~ 390 FPS.

 

Thanks again :)

 

 

In your diagram yours looks better, but you can't just eye it you actually have to test it.

 

Do you use the M-nub w/ yours? Because I find that due to the M-nub's softness, my hop doesn't actually adjust to much; rather, the M-nub just becomes squished as I turn the hop-up dial towards maximum.

 

Yup. Your problems probably come from a system that doesn't have a large range of motion in the hop. The M4 has a huge range of motion so you can adjust the hop a lot. Some other systems only adjust the hop a little, and I suspect thats why you're not seeing a huge range of adjustment.

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In your diagram yours looks better, but you can't just eye it you actually have to test it.

 

 

 

Yup. Your problems probably come from a system that doesn't have a large range of motion in the hop. The M4 has a huge range of motion so you can adjust the hop a lot. Some other systems only adjust the hop a little, and I suspect thats why you're not seeing a huge range of adjustment.

Hmm.. But wouldn't an R-hop like the top picture be better? I'd think this would have more contact on the BB... If I installed an R-hop like the one on the bottom, I'd think the BB would only make contact <AT> one spot (the top), whereas an R-hop like the top one would have contact the BB at many more sides (or angles).

 

I started properly testing my R-hop, and it looks like it's doing slightly better than my old hop, but just by a small margin (increase in 10-15' range).

 

And also, what is best to file or sand down the feet of the R-hop? I'd think it would be hard to do so with a hand file or 400 Grit sandpaper - is a Dremel OK? (What would you use if you didn't have those sharp knives :a-wink:).

 

Thanks

 

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If you read through it I retract my comment then :)

 

 

But as Airborne says, higher grit sand paper(600+) helps with evening everything out and I had the same problem with consistency in my shots using just 400 on mine as well. They shot farther than my .25's ever did, but I didn't get the godlike consistency that was mentioned; and actually I ended up ruining my first three patches I bought because I tried pulling those little nubs off with the tweezers.

Edited by Jerichow

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I have actually read a majority of this thread, but I just wanted to see what you guys thought :)

 

I've actually tried the 'tweezers' method of cutting the legs (where you stick the CP in tweezers that are then secured in a vice), but that ended up badly. So far, I've been Dremeling the legs of my R-hops with a fine sanding drum, but I just want to see what you guys thought about it.

 

Another thing I see a lot with my patches (after sanding or filing them) is rubber 'shards'. Basically, after I use sandpaper, a file, or the Dremel, I always see these left over bunches of rubber (kind of like the left over rubber from erasing something) and I can pry them off with tweezers, but it creates inconsistencies in the contact patch. Maybe I'm just using to sharp (lower grit) sandpaper and files.

 

Also, should I be using diamond files? The ones I have are pretty non-diamond low grit $20 set of 'General' hand files.

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You need to use high grit sand paper for finishing it. This will stop the bunches of rubber and pitting. I have found that 400 grit is good for gross adjustments and 600 grit is good for finishing/fine adjustments when sanding the IR hop. I have found that both grits are a tad too rough for the regular R hops and am in search of the recommended 800 grit.

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Sorry to bump this, but my old website is having issues and I'm updating it to a new one. Please update your bookmarks and spread the word that the new site is: https://sites.google.com/site/hsarmory/

 

Thanks everyone. Sorry for the inconvenience and the mess. THIS HAS CAUSED NO SERVICE INTERRUPTION.

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What material are the contact patches made out of? What about the temperature patches? I'm thinking of making my own.

If he told you, then everyone would make their own and no one would buy from him lol. There are lots of things you can use, just do a little experimentation of your own. I've had some pretty good results from rubber grips from pens.

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I encourage you to experiment. The one thing I should warn you about is a lot of materials aren't pure rubber, they contain additives which can and will damage your barrel. These additives were put in there for a variety of different reasons, and basically as bbs pass they pull out these tiny particles which chew away at your barrel. Avoid things like that.

 

By the way earlier in this thread there was a heated discussion on this topic and I highly recommend you look back a bit and read that.

Edited by hunterseeker5

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I'd like to ask a question on theory:

 

Has anyone bothered to compare chrono readings between hop off, normal hop on to what ever setting is appropriate, and whatever setting is appropriate for r-hop? I'm thinking perhaps the fact that the r-hop has such little presence in the barrel may simply allow less energy to be taken from the bb, thus lending a slight range boost.

 

Second question, has anyone taken actual range measurements (like the distance the bbs go), as opposed to "effective range" measurements? Perhaps R-hop gives the illusion of increased range by increasing the distance at which specific targets can be hit.

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I'd like to ask a question on theory:

 

Has anyone bothered to compare chrono readings between hop off, normal hop on to what ever setting is appropriate, and whatever setting is appropriate for r-hop? I'm thinking perhaps the fact that the r-hop has such little presence in the barrel may simply allow less energy to be taken from the bb, thus lending a slight range boost.

 

Second question, has anyone taken actual range measurements (like the distance the bbs go), as opposed to "effective range" measurements? Perhaps R-hop gives the illusion of increased range by increasing the distance at which specific targets can be hit.

 

Let's go about this from a "physics" perspective. There is only a single rpm which will give you "level" flight, and a small range which will give you a slight overhop/underhop which is acceptable, which means that every bb of the same mass and energy (and from a correctly tuned hop) with the same energy (linear kinetic) and rpm (rotational kinetic) will go the same distance which means they will have the same range. The advancements in hop increase effective range, which is done by reducing inefficiencies in the system. Some hops might have less slip and therefore less waste in energy (goes to heat) so you might see a slight increase in fps, but a bb with the same muzzle velocity and the same angular velocity (and of course same mass) will have the same trajectory.

Edited by krap101

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Let's go about this from a "physics" perspective. There is only a single rpm which will give you "level" flight, and a small range which will give you a slight overhop/underhop which is acceptable, which means that every bb of the same mass and energy (and from a correctly tuned hop) with the same energy (linear kinetic) and rpm (rotational kinetic) will go the same distance which means they will have the same range. The advancements in hop increase effective range, which is done by reducing inefficiencies in the system. Some hops might have less slip and therefore less waste in energy (goes to heat) so you might see a slight increase in fps, but a bb with the same muzzle velocity and the same angular velocity (and of course same mass) will have the same trajectory.

This is a bit oversimplified, you should add the assumption that all of those bbs should have the same spherical characteristics and be experiencing the same amount of vibration. They should also be free of internal voids for this statement as well.

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This is a bit oversimplified, you should add the assumption that all of those bbs should have the same spherical characteristics and be experiencing the same amount of vibration. They should also be free of internal voids for this statement as well.

 

Would you like me to complicate it for you?

 

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Would you like me to complicate it for you?

Wow that's a pretty snide attitude. I may not be an engineer but I am a PhD candidate in microbiology so I am not an idiot. The vibration is necessary to take into account because this is probably one of the most significant ways that energy can be bled off in a traditional system and one of the only ways a traditional incidental hop and a R-hop differ. A tradtional hop will cause the bb to have more collisions with the barrel on its way out, each one causing vibration. After the bb has left the barrel this vibration will cause more bleed off of kinetic energy from the bb. An R-hop or Flat hop will reduce this vibration because the bb tends to ride the top of the barrel (the same reason an lrb will give more range). So in this case a bb with the same fps leaving a traditional system as a bb from an R-hopped system will lose more energy. I think that is pretty significant, don't you? Voids in the bbs and not being perfectly spherical will compound the problem. So my point was that by simplifying it too much you are missing the very thing which makes an R-hop or flat hop special.

 

The people on this forum do not need to have things overly simplified. They are intelligent people who would like a complete explanation. The ones who can't understand are not bothering to read this thread and can just buy the products.

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Wow that's a pretty snide attitude. I may not be an engineer but I am a PhD candidate in microbiology so I am not an idiot. The vibration is necessary to take into account because this is probably one of the most significant ways that energy can be bled off in a traditional system and one of the only ways a traditional incidental hop and a R-hop differ. A tradtional hop will cause the bb to have more collisions with the barrel on its way out, each one causing vibration. After the bb has left the barrel this vibration will cause more bleed off of kinetic energy from the bb. An R-hop or Flat hop will reduce this vibration because the bb tends to ride the top of the barrel (the same reason an lrb will give more range). So in this case a bb with the same fps leaving a traditional system as a bb from an R-hopped system will lose more energy. I think that is pretty significant, don't you? Voids in the bbs and not being perfectly spherical will compound the problem. So my point was that by simplifying it too much you are missing the very thing which makes an R-hop or flat hop special.

 

The people on this forum do not need to have things overly simplified. They are intelligent people who would like a complete explanation. The ones who can't understand are not bothering to read this thread and can just buy the products.

 

Well, that's what staying up for 12 hours doing matlab code would do, but anyways... I'll leave you with one question. What is the difference between implied assumptions and over simplification? I've fully defined the system at least a dozen times, and I shouldn't have to cut the problem out of stone every time I try to explain something as simple as the relationship between rpm, velocity and trajectory, and the extra assumptions were not relevant to my point.

 

 

 

 

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I'd like to ask a question on theory:

 

Has anyone bothered to compare chrono readings between hop off, normal hop on to what ever setting is appropriate, and whatever setting is appropriate for r-hop? I'm thinking perhaps the fact that the r-hop has such little presence in the barrel may simply allow less energy to be taken from the bb, thus lending a slight range boost.

 

Second question, has anyone taken actual range measurements (like the distance the bbs go), as opposed to "effective range" measurements? Perhaps R-hop gives the illusion of increased range by increasing the distance at which specific targets can be hit.

 

 

Your first question refers to power output, and is actually a little more complicated than you first expected. The short answer is that, depending on your gun's tune, you can seen an increase, decrease, or no real change in power output. Why? The same reason that you can tune your gun to shoot about 10m/s faster with the hop on than off if you like: obstructing the bb's path while you build pressure in the cylinder can increase power if your gun is designed for it. Of course most people don't optimize their guns for this, which is why most people see an FPS boost when they turn their hopup off. If your gun is in that category you WILL see an FPS boost from using the R-hop. It won't be a huge one, probably, but you can often measure it.

 

A number of people have actually, and noted a range increase. Why should you be skeptical of those numbers? Because if the gun didn't have the same barrel, same point of impact, same blahblahblah it might not have been a perfectly accurate test. I accept the general trend though, which coincides with my own observations, that show the R-hop appears to be able to increase "level" flight for some reason we don't understand. Of course there are people who like to live in a place called theory who will tell you this is impossible. So you can either feel free to take it from someone who talks about the R-hop based on how they think the world should behave, or you can just try it and see. :) The EFFECTIVE range increase is not really debatable as its a function of increased accuracy and THAT is much more significant.

 

 

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A number of people have actually, and noted a range increase. Why should you be skeptical of those numbers? Because if the gun didn't have the same barrel, same point of impact, same blahblahblah it might not have been a perfectly accurate test. I accept the general trend though, which coincides with my own observations, that show the R-hop appears to be able to increase "level" flight for some reason we don't understand. Of course there are people who like to live in a place called theory who will tell you this is impossible. So you can either feel free to take it from someone who talks about the R-hop based on how they think the world should behave, or you can just try it and see. :) The EFFECTIVE range increase is not really debatable as its a function of increased accuracy and THAT is much more significant.

 

I still believe if you took a fps and rpm reading, it would make perfect sense.

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I still believe if you took a fps and rpm reading, it would make perfect sense.

 

 

Oh thank god I have you there to tell me that because when I first started seeing abnormal behavior my assumption was that it was just magic. You really think I'm THAT incompetent that, even after referring to FPS tests, I didn't bother to check output as a possible cause of the increased range? REALLY? I'm sorry but in science we really strive not to discard evidence because it doesn't support our theory, we modify/discard theories based on evidence. If everyone thought this way we'd still be executing people for claiming the earth revolved around the sun.

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Why should you be skeptical of those numbers?

 

Because I haven't seen them. If you could direct me toward them, I would much appreciate it.

 

I have no dispute with the fact that R-hop increases effective range, I am simply suggesting that the appearance of greater range may be much simpler than the highly convoluted theories previously suggested. Perhaps I'm simply to zealous in my pursuit of Occam's razor.

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I posted a few pages back that my buddies M14 that I upgraded to shoot 425fps w/ .20g bbs was achieving level flight till around 300-325ft using R-hop and .36g bbs. Our distance was measured through Google Maps so it isn't precise, but it was defiantly far in excess of the 200-250ft range that you would normally see with the same setup minus the R-hop.

 

There is also a link video a page or two back by a guy who shot his son (willingly of course) and different ranges, maxing out around the 300ft mark.

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