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Why Barrel Length Doesn't Affect Accuracy


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46 replies to this topic

#1 jvarma

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Posted 16 June 2009 - 08:44 PM

After reading the pinned thread about the supposed "myth" that barrel length affects accuracy I was surprised by how little many airsofters and shooters in general know about ballistics. Hoping to find evidence from both sides of the argument I saw the thread simply degenerate into little more than a large group of people claiming that barrel length "must" affect accuracy because it just seems like it should. Starting from the beginning it appears as if no one has realised what our fellow airsofters in england have known for a while. After reading the entire thread no one seemed to be able to explain in a scientific and factual manner why barrel length was so important. They simply took it as a "fact" that had been around longer than anyone could remember and one that could not be argued against. What follows is a more in depth review of ballistics in real and air weapons.

Humans, being primarily visual creatures, obtain most of their information from what they see. As rifles and sniper weapons have usually had long barrels we seem to associate a long barreled weapon with accuracy. Why if not for accuracy do we select long weapons for long range applications? The answer is simple: a longer barrel allows the firearm to more effectively use the propellant gases therefore producing higher velocities and longer ranges. The true key to accuracy is consistency thus variables produce inaccuracy. The most prized barrels are those that have no defects and are the most consistent. Whether they are the short barrels of 22 target pistols or the long barrel of a precision sniper rifle. Many accurate guns are pistols - and many target pistols rival the accuracy of any rifle. Unfortunately things are a little bit more complicated in airsoft. An airsoft gun can be likened to an early musket. Both have smooth bore barrels. In the early days muzzle loading firearms were loaded with a slightly undersized ball this allowed for easy ramming down the barrel. When fired the ball would bounce around in the barrel due its loose fit - the same happens in airsoft. After the invention of rifles bullets were given an expanding skirt which would flare out creating a snug fit and more accuracy. In airsoft the tightbore barrel produces a similar effect. Another accuracy booster was the rifling the spinning motion of the bullet gave it stability like a football and longer range. The airsoft equivalent of this is hop up. What "justification" do people give when they use long barrel? Most say that since the barrel guides the projectile the longer the projectile is in the barrel the more it has been "guided" and the straighter it will go. The direction a projectile actually goes when it leaves the barrel is based on the direction it was going last. An object in flight will only change direction if factors influence it in flight. The main factor is gravity whish pulls the bullet down, other factors include wind. Because of this once a projectile has been in the barrel for a few inches it is already travelling in one direction a longer barrel does not make it travel "more" in that direction. Compare this to a straight line. A line with 0 deviation cannot deviate any less. The direction a projectile will go in is only affected by the last surface it came in to contact with. A barrel that is loose at the beginning and tight at the end will group the same as a barrel that was tight the whole way through. Consider a barrel with a curve at the end. No matter how long the barrel is before the curve the projectile will still curve the same amount as a shorter barrel with the same curve. This is why a good crown is the key to a good barrel. The bit of barrel a bb hits will determine whether that bb hits its target.

If you still don't believe me look at the various proffessionals that have the same idea:

This link is to an article by Ryan Cleckner


http://www.snipersch...-barrel-length/

Drop your g3s and m16s because the extra barrel length is only slowing you down. Next time you visit your local airsoft field try asking a friend if you can borrow his mp5. You won't regret it...

-jvarma





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#2 osu5312

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Posted 16 June 2009 - 08:57 PM

What you theoretically said is a TM MP5K with a PDI 6.01mm barrel and stock hop-up should have the range and accuracy of a TM M16 with a PDI 6.01mm barrel and stock hop-up. Great post, I just still beleive that a bug difference in big length (like 250mm or more) will affect accuracy and range. While a minimal difference (249mm or less) won't have that big of a difference.
When talking about airsoft, throw real steel facts out of thw window.

Sorry if there are typos I'm very tired.
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QUOTE (M249Dude @ Sep 13 2009, 09:01 PM) <{POST_SNAPBACK}>
so based on what ur saying, echo 1 didnt build their own P90? they bought it from another company and magically molded their trades onto the metal body so cleanly?

#3 SupaTIM

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Posted 16 June 2009 - 08:59 PM

I'll believe you when you do tests and post up some hard evidence.
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#4 GunMonkeys

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Posted 16 June 2009 - 09:07 PM

So it applies to real gun's but not airsoft guns? I didn't read the whole thing but cool if it's real.
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#5 jvarma

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Posted 16 June 2009 - 09:24 PM

QUOTE (SupaTIM @ Jun 16 2009, 08:59 PM) <{POST_SNAPBACK}>
I'll believe you when you do tests and post up some hard evidence.


I understand and agree with you. I too would like to see a test. Unfortunately I don't have two guns of the same type. The best I can do to reassure you is say that quite a few people who have tested a whole line of aegs (tm for example) would say there is only a small variation in accuracy. Richard horgan states in his review on arnies airsoft that the TM mp5k is as accurate as its larger brother:

"The first thing you think when you hear "MP5K" is short barrel. This SHOULD mean it's inaccurate, however, for some reason, its as accurate as an Mp5a5, or a similar sized AEG. Why? Marui magic pixie dust is all I can think of. You can hit a man sized target at 40 meters without much difficulty, and if you have the hop set up correctly, you can get people at as far as 50 meters!"

I encourage someone to do a test and post the results on this thread- take two aegs from the same company based on the same model - an m4 and an m16 would be good- and test them at 25 feet and 50 feet. This short range will limit wind/ weather factors and also stop the m16s higher velocity (the only effect of a longer barrel) from outranging the m4. Even at long range the differnce in accuracy would be negligible.
The aegs should of course be stock with no upgrades.
If anyone has any further questions feel free to ask.


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#6 jvarma

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Posted 16 June 2009 - 09:25 PM

QUOTE (GunMonkeys @ Jun 16 2009, 09:07 PM) <{POST_SNAPBACK}>
So it applies to real gun's but not airsoft guns? I didn't read the whole thing but cool if it's real.

Yeah it was a bit long, the theory applies to both real and airsoft guns. I just wanted to go in depth so as not to miss any important points.
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#7 hydralover

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Posted 16 June 2009 - 10:07 PM

I don't think it was long at all. A very interesting read.
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#8 namloot

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Posted 16 June 2009 - 10:13 PM

QUOTE (jvarma @ Jun 16 2009, 10:24 PM) <{POST_SNAPBACK}>
The best I can do to reassure you is say that quite a few people who have tested a whole line of aegs (tm for example) would say there is only a small variation in accuracy

My son and I have 7 TM AEGs and I agree with this. We've found that longer barreled guns tend to be a bit more accurate, but not enough to make a tactical difference on the field.

All of our TM AEGs, when stock, could hit a man sized target 9 hits out of 10 shots at 125 feet and 5 hits out of 10 shots at 150 feet, except for the M14 which got 9 hits out of 10 shots at 150 feet. The M14 does have a 500mm inner barrel but arguabley has the best hop up and front end design of any AEG.

The TM P90 with its' 247mm barrel is just as accurate as the TM AUG with its' 509mm barrel.

Upgraded, my TM M14 (500mm barrel) is the most accurate, then my son's TM AUG (509mm barrel), my custom TM G36KV (363mm barrel), my son's G&P M4 (363mm barrel) and least accurate is my TM AK47 (455mm barrel).

They all shoot around 420-425fps w/ .20g BB and all 5 can hit a man sized target 9 hits out of 10 shots at 225 feet. The different models of AEGs have different body, gearbox and hop up designs, so a direct comparison can not be made. However, it is clear the accuracy of an AEG is not based entirely on its' barrel length.

Good thread.

Edited by namloot, 16 June 2009 - 10:31 PM.

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#9 GoLgo 13

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Posted 16 June 2009 - 10:26 PM

Real steel ballistics do not paralell with airsoft guns so reading what competent gunsmiths have to say about accuracy is a absolute waste of time.

However I will say that barrel length has nothing to due with accuracy OR RANGE in the airsoft world. Nor does the inner diameter help jack :pain:. The consistency of the hop rubber and inner diameter/quality barrel matter.

I have said it plenty of times on here. After working on and owning dozens and dozens of airsoft replicas I've concluded that barrel length does not help anything. I have a TM Mp5k with a 229mm Systema barrel that shoots just as accurate and far as my Star SL8-6 replica with a 509mm edgi barrel to name one extreme example.


The best barrels I have ever used are Tokyo marui and Systema, and I have used a myriad of barrels such as Prometheus, Systema, Marui, MAdbull, Guarder, Classic army, EDGI, DBC, Star etc etc...
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#10 Mental Medic

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Posted 16 June 2009 - 10:46 PM

I've heard though that rifled airsoft barrels are exempt from the "length vs quality of barrel" rule. Does anyone have contradicting evidence?
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#11 jvarma

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Posted 16 June 2009 - 11:20 PM

QUOTE (GoLgo 13 @ Jun 16 2009, 10:26 PM) <{POST_SNAPBACK}>
Real steel ballistics do not paralell with airsoft guns so reading what competent gunsmiths have to say about accuracy is a absolute waste of time.

However I will say that barrel length has nothing to due with accuracy OR RANGE in the airsoft world. Nor does the inner diameter help jack pain.gif. The consistency of the hop rubber and inner diameter/quality barrel matter.

I have said it plenty of times on here. After working on and owning dozens and dozens of airsoft replicas I've concluded that barrel length does not help anything. I have a TM Mp5k with a 229mm Systema barrel that shoots just as accurate and far as my Star SL8-6 replica with a 509mm edgi barrel to name one extreme example.


The best barrels I have ever used are Tokyo marui and Systema, and I have used a myriad of barrels such as Prometheus, Systema, Marui, MAdbull, Guarder, Classic army, EDGI, DBC, Star etc etc...

I agree that real steel ballistics do not parallel airsoft but I compared the two because they share some similarities, mainly both are similar in that barrel length doesn't effect the accuracy of either one.
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#12 jvarma

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Posted 16 June 2009 - 11:26 PM

QUOTE (Mental Medic @ Jun 16 2009, 10:46 PM) <{POST_SNAPBACK}>
I've heard though that rifled airsoft barrels are exempt from the "length vs quality of barrel" rule. Does anyone have contradicting evidence?


Interesting, I had never heard of rifle airsoft barrels. I am not sure, it would seem that because barrel length does not affect accuracy in real rifles the same theory would apply here. I can't imagine that a rifled airsoft barrel would be very effective because, as I stated earlier, the main reason rifling imparts a spin to bullets is because the soft lead skirt expands to fit the rifling. Since bbs are hard plastic they should merely roll over the grooves and not get much spin. You might also lose velocity due to air escaping around the bb
Most importantly: Where would you obtain a rifled airsoft barrel?
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#13 N/A

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Posted 16 June 2009 - 11:30 PM

QUOTE (jvarma @ Jun 16 2009, 08:26 PM) <{POST_SNAPBACK}>
Interesting, I had never heard of rifle airsoft barrels. I am not sure, it would seem that because barrel length does not affect accuracy in real rifles the same theory would apply here. I can't imagine that a rifled airsoft barrel would be very effective because, as I stated earlier, the main reason rifling imparts a spin to bullets is because the soft lead skirt expands to fit the rifling. Since bbs are hard plastic they should merely roll over the grooves and not get much spin. You might also lose velocity due to air escaping around the bb
Most importantly: Where would you obtain a rifled airsoft barrel?


He's probably talking about the TK twist barrels. Those barrels are "rifled" but not in the sense that it spins the projectile, but in the sense that it spins the air around the bb causing the bb to not come in contact and therefore not bounce off the barrel.
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#14 SupaTIM

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Posted 16 June 2009 - 11:31 PM

I think he's referring to the Tanio Koba Twist barrels.
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#15 bullpupfan

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Posted 17 June 2009 - 12:57 AM

so by this, my mp7 should have the same accuracy as my m14...also would a p90 be as accurate as a psg1??...so does make bullpup pointless in airsoft, where m4's and mp5's are just as accurate as l85's and aug's???.... and Golgo, could u pm me about that barrel comment, im interested about which barrel type 2 buy
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#16 BigEd

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Posted 17 June 2009 - 05:29 AM

QUOTE
What "justification" do people give when they use long barrel? Most say that since the barrel guides the projectile the longer the projectile is in the barrel the more it has been "guided" and the straighter it will go.


Deceleration begins when the projectile exits the barrel. The greater the pressure, the longer the barrel, the heavier the projectile, the more accurate. It is a balancing act.

///ed///
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#17 osu5312

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Posted 17 June 2009 - 07:27 AM

QUOTE (jvarma @ Jun 16 2009, 10:24 PM) <{POST_SNAPBACK}>
The aegs should of course be stock with no upgrades.
If anyone has any further questions feel free to ask.

Shouldn't you get a barrel that has little to no deviations? Because, one barrel might have more deviations and the other one has less.
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QUOTE (M249Dude @ Sep 13 2009, 09:01 PM) <{POST_SNAPBACK}>
so based on what ur saying, echo 1 didnt build their own P90? they bought it from another company and magically molded their trades onto the metal body so cleanly?

#18 TheAirsoftLoki

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Posted 17 June 2009 - 03:09 PM

QUOTE
an m4 and an m16 would be good- and test them at 25 feet and 50 feet. This short range will limit wind/ weather factors and also stop the m16s higher velocity (the only effect of a longer barrel) from outranging the m4

I think you mean "from being more precise" not outranging. http://www.airsoftfo...6#entry18053656

If barrel length did not matter, then why would airsoft snipers spend $80 for an extended outer barrel, to turn the gspec into a full length, spend around $20-$30 for a longer tightbore versus the shorter version, and 100 for a bore up to be able to use a longer barrel.

Edit: Now re-reading my post I realize that some one will say when responding: To get more fps, because fps owns. I have an article that those who think that should read. Click Me!

Edited by TheAirsoftLoki, 17 June 2009 - 03:26 PM.

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#19 jvarma

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Posted 17 June 2009 - 03:56 PM



This is the main problem, the reason people spend more money on on a longer barrel is because they associate barrel length with range and accuracy. They think that by making their gun bigger it will make it "better". Unfortunately they don't know any better and actually believe their upgrades are making a difference. Regarding the article, it was interesting but not without faults. A higher fps gun does add a little bit to effective range because it can utilise a heavier bb that is less affected by wind. Using a 0.2gram in an upgraded gun however (as suggested by the article) won't really help. The main upgrades you want are: a tighbore barrel for accuracy and good hop up for range.
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#20 TheAirsoftLoki

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Posted 17 June 2009 - 04:04 PM

So what you are saying is that if I use a 4-in MP5k barrel in my bar-10, it will be as precise as the stock barrel?
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#21 The Irish Marksman

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Posted 17 June 2009 - 04:12 PM

QUOTE (osu5312 @ Jun 17 2009, 08:27 AM) <{POST_SNAPBACK}>
Shouldn't you get a barrel that has little to no deviations? Because, one barrel might have more deviations and the other one has less.


I completley agree with osu. Two edgi barrels would probably be best.
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#22 osu5312

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Posted 17 June 2009 - 04:16 PM

QUOTE (The Irish Sniper @ Jun 17 2009, 05:12 PM) <{POST_SNAPBACK}>
I completley agree with osu. Two edgi barrels would probably be best.

PDI is more consistent that Edgi, they would be good though. We just want the least amount of variables possible.
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READ THIS BEFORE YOU MAKE ANTOHER TOPIC ABOUT WHY TM IS SO GOOD.
QUOTE (M249Dude @ Sep 13 2009, 09:01 PM) <{POST_SNAPBACK}>
so based on what ur saying, echo 1 didnt build their own P90? they bought it from another company and magically molded their trades onto the metal body so cleanly?

#23 jvarma

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Posted 17 June 2009 - 04:53 PM

QUOTE (TheAirsoftLoki @ Jun 17 2009, 04:04 PM) <{POST_SNAPBACK}>
So what you are saying is that if I use a 4-in MP5k barrel in my bar-10, it will be as precise as the stock barrel?



That depends on the tightness of the stock barrel. I am saying that if you take two barrels of the same quality - which are different lengths (tm mp5 and mp5k for example) they will perform the same.
If the bar 10 has a barrel of of the same bore diameter, material and quality as the mp5k barrel then yes.
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#24 jvarma

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Posted 17 June 2009 - 04:55 PM

QUOTE (osu5312 @ Jun 17 2009, 04:16 PM) <{POST_SNAPBACK}>
PDI is more consistent that Edgi, they would be good though. We just want the least amount of variables possible.


Get an aeg and try out two tightbores from the same company with different lengths. The results should be consistent.
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#25 namloot

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Posted 17 June 2009 - 05:45 PM

QUOTE (osu5312 @ Jun 17 2009, 08:27 AM) <{POST_SNAPBACK}>
Shouldn't you get a barrel that has little to no deviations?

There is no such thing as a barrel with no deviations.
The quality of a good inner barrel has reached the point where making them any straighter, smoother or rounder will not make them more accurate because of the limitations reached with BB quality.

The tolerances in BB roundness, balance, size and weight is many, many times more then the deviation in straightness, roundness and smoothness of all of the top make inner barrels.

BB quality if the limiting factor in airsoft accuracy, not inner barrel quality. Simply put, the quality of BBs suck when compared to the quality of good inner barrels.

QUOTE (The Irish Sniper @ Jun 17 2009, 05:12 PM) <{POST_SNAPBACK}>
I completley agree with osu. Two edgi barrels would probably be best.

That is not true.
Once the quality of an inner barrel reaches a certain level of straightness, roundness and smoothness, there will be no noticeable difference between them. If you were to buy any of the top brands, Prometheus, Madbull, PDI, Systema, CA or EdGI, from an accuracy standpoint, they would all shoot the same.

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#26 yee245

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Posted 17 June 2009 - 05:45 PM

QUOTE (TheAirsoftLoki @ Jun 17 2009, 05:04 PM) <{POST_SNAPBACK}>
So what you are saying is that if I use a 4-in MP5k barrel in my bar-10, it will be as precise as the stock barrel?

Yes. Well, actually, just maybe, since I don't know how the stock BAR-10 is. http://www.airsoftfo...od-t144789.html.

Not really related to the videos linked to in that thread, but I have some issues with the notion that barrel length and inner diameter make absolutely no difference to accuracy or consistency. I would like to see the accuracy tests of a 6.28mm barrel compared to a 6.03mm barrel of the same length. Also, I would like to see the accuracy tests of a fairly common 509mm barrel and a custom 25mm barrel (yes, an inch long) of comparable inner diameter. In both tests, the gun used should be the same, in that the gearbox and hop up are the same during both tests, assuming the cylinder can take it. Also, the BB's used in the test should be the same. Tell me that the results from those two tests come to the conclusion barrel length and inner diameter make no difference. I guess with that second test, the velocity is going to significantly affect things, but still, that is something that is directly affected by changing a barrel. With enough time and deception, I'm sure a video can be made that shows exactly that (that there is no difference).
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#27 Stealthmaster14

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Posted 17 June 2009 - 05:47 PM

QUOTE (osu5312 @ Jun 17 2009, 05:16 PM) <{POST_SNAPBACK}>
PDI is more consistent that Edgi, they would be good though. We just want the least amount of variables possible.


Edgi has tighter tolerances than PDI.

I think what people are missing here is that you need to use two barrels of nearly identical quality, (IE Edgi M16 length barrel vs an Edgi MP5K length barrel) if you don't do this, the test won't be accurate. The barrels must be used in the same gun because different hop up units will give different performance.

I personally think that barrel length does affect accuracy and range quite a bit. Definitely not as much as real guns, but I believe it has an affect.

Think about it, if you have a 10 inch barrel vs a 30 inch barrel and you are shooting at a target from 50 feet, which do you think will have a better chance of hitting the target? Makes sense in my mind.

Edited by Stealthmaster14, 17 June 2009 - 05:52 PM.

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#28 osu5312

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Posted 17 June 2009 - 05:49 PM

QUOTE (jvarma @ Jun 17 2009, 05:55 PM) <{POST_SNAPBACK}>
Get an aeg and try out two tightbores from the same company with different lengths. The results should be consistent.

I'm flat broke :(
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READ THIS BEFORE YOU MAKE ANTOHER TOPIC ABOUT WHY TM IS SO GOOD.
QUOTE (M249Dude @ Sep 13 2009, 09:01 PM) <{POST_SNAPBACK}>
so based on what ur saying, echo 1 didnt build their own P90? they bought it from another company and magically molded their trades onto the metal body so cleanly?

#29 jvarma

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Posted 17 June 2009 - 09:42 PM

QUOTE (Stealthmaster14 @ Jun 17 2009, 05:47 PM) <{POST_SNAPBACK}>
Edgi has tighter tolerances than PDI.

I think what people are missing here is that you need to use two barrels of nearly identical quality, (IE Edgi M16 length barrel vs an Edgi MP5K length barrel) if you don't do this, the test won't be accurate. The barrels must be used in the same gun because different hop up units will give different performance.

I personally think that barrel length does affect accuracy and range quite a bit. Definitely not as much as real guns, but I believe it has an affect.

Think about it, if you have a 10 inch barrel vs a 30 inch barrel and you are shooting at a target from 50 feet, which do you think will have a better chance of hitting the target? Makes sense in my mind.


It may seem like a longer barrel would be more accurate but it the results of many tests are actually surprising. If you really though about it you probably
wouldn't be able to come up with a true reason why a longer barrel is more accurate. Since I heard about the theory I have had doubts myself and after a few minutes thinking about it I continued to feel that a longer barrel should be more accurate, then I realised that no matter how hard I thought I just couldn't figure out why. Thats when I decided to just accept it.
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#30 Kilo Oscar Tango

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Posted 18 June 2009 - 10:13 AM

This is very interesting indeed, but I wouldn't suggest everyone grab MP5ks.

The decision of rifle or next rifle usually has a lot to do with a loadout or real counterpart, so even if an M16A4 is less maneuverable than a Tanker M4 it's more realistic in a Marine loadout. For the sake of realism a M14 would be picked over a shorter rifle as a DMR, but then the real characteristics become transposed in the mind of the owner, and myths begin. Why realism you ask? Because Airsoft was based on Milsim and realistic play and those physical characteristics, length, weight, alter the game for that player, changing his play style, speed, and so on, which changes the game and ultimately helps teamwork and leads to a better time (hopefully).

So as this thread basically eliminates the need for "Which AEG is the Most Accurate" threads it doesn't change much, just puts a few readers at ease that they don't have to carry a M14 at all times to hit a target at range.
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#31 forrest225

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Posted 18 June 2009 - 03:59 PM

I personally believe that barrel length does not effect accuracy directly, but I still feel an airosfter with an M14 will have more accurate shots at long range than one with an MP5 because IMO its much easier to aim a full sized rifle.

But hey, thats just me a-wink.gif
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#32 ArmorerKen

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Posted 18 June 2009 - 04:57 PM

Barrel length DOES effect velocity with heavier ammo, which then effects range. The hop spin is nothing like the spin of a bullet it is a much closer to the spin a bowler gives a ball to hook it into the pins, only in our case we are spinning it up to counteract gravity pulling it down. I find for a .2 to .25 gm BB at 400fps a short barrel is just fine. From real world experiance I found the m4/mp5/AK beta Spetznaz length tightbore barrels were the most accurate with low weight ammo. I think the mass of the BB resisting the air pressure is minimal, but the BB flys straighter when the cushion of air that is trying to escape around it is very smooth an consistent. To Achieve that you need a perfectly true barrel with no variations in inner diameter from end to end. The BB is nothing like a rifled bullet, ideally it will not touch the walls of the barrel as it moves down it but instead will ride on a hard cushion of air that is trying to squeeze past the BB to escape out the front of the barrel. Tightbore barrels help make that pressure behind the BB greater and make the air escaping around the BB higher pressure as well. Combining this with barrel that is true from end to end and you have a BB that has a better chance of keeping the spin the hop unit gave it by not touching anything else from the hop unit to the target, including the barrel.

I do not know the exact physics behind this next part, but it is true. Lighter BB's around .25gm can only take so much velocity before they start to do weird things in flight. Around 400fps is near the limit that a .2gm BB will have good aerodynamics. Heavier BB's will fly farther straighter but need more kinetic energy to do this. You can transfer more energy to your BB from your spring two ways that I know, decrease the time it takes you to compress the volume of air in the cylinder, or increase the volume of air in the cylinder while compressing the entire volume in the same amount of time. After a point trying to compress a low volume of air faster and faster means banging on the internals running a heavy spring, and the small volume of air slows the piston head little before it slams into the cylinder head. A larger volume of air in the cylinder needs a longer barrel to match, but will make that piston head slow as it tries to force more air through the nozzle creating a higher internal pressure from the same spring. Less wear on internals, higher air pressure in barrel and with a properly installed barrel that has been shimmed to be perfectly flat and straight inside the AEG you get very accurate long range shots.

So a longer barrel can help but only if everything else is set up right and the ammo weight is suitable. Running a Tanaka m700 at near 600fps with .25, a .48gm BB from same gun will fly like its ridding a laser beam while at a much lower FPS. And punch through an aluminum can out past 200 feet. My DMR AEG at 460fps with .2gm BB's shoots .36 BB's perfectly straight but a .2 will after a short distance of straight flight take a weird turn in a random direction as the low weight BB passes through a velocity were it seems to create turbulence for itself. I suspect its around the 440fps mark its happening like 30yards out from the barrel so almost instantly the BB is not flying right at that speed.

Anyway as you can see from my (convoluted) explanations it has many variables and its nothing to do with real steal.
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#33 TheAirsoftLoki

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Posted 18 June 2009 - 05:21 PM

Actually, I can see your logic now. I can see why longer barrels would not be as accurate as intermediate length barrel. As anyone who read the TK Twist thread or has examined their barrel closely would notice, BB's are a tiny bit smaller than the barrel. That means that when shooting, they would bounce around more, and with each bounce, the path of the BB would change a little, and the impact might "rob" the BB of a small amount of energy. This would make the BB more susceptible to wind and it would already on the wrong path. However, I am not saying that your super 1337 mp5k will pwnzorz the PSG-1 in precision. The shorter the barrel, the less distance you will have to guide the BB in the general area that you want it to go in. I personally believe that 300mm-400mm is the optimum length for the balance of precision and power.
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#34 Stealthmaster14

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Posted 18 June 2009 - 05:36 PM

BBs DO touch the inner barrel, they bounce up and down. I don't think bbs every settle on a cushion of air. (unless you have a TK barrel, even then I doubt it) TCF doesn't think bbs settle on a cushion. There's a big topic on ASR about the physics and all that good stuff. :)

Edited by Stealthmaster14, 18 June 2009 - 05:37 PM.

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Custom JG G36K-Madbull 6.03mm 363mm tightbore, Falcon 70 degree bucking, Deans, Guarder spring guide, Guarder SP110, Element POM bearing piston head, #14 O ring, longer air nozzle, SRC type 0 cylinder, dream army 7mm bushings, AOE adjusted
Youtube channel-http://www.youtube.com/user/Stealthmaster15?feature=mhum

Airsoft is pretend war, but for big boys

#35 ArmorerKen

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Posted 18 June 2009 - 06:01 PM

yes in stock guns and guns poorly tuned they bounce all over the place, and you get variables in hop spin and trajectory out the front because of it. As well any slight imperfection in the BB will cause it to disrupt the high pressure air trying to escape around it and it will touch the barrel. You MUST use polished high grade BB's if you want accuracy. In a clean KN 650mm tightbore using polished .36gm BB's my DMR aeg fires sabots. The BB does not bounce it is cushioned on high pressure air and comes out on the same trajectory with the same spin every shot. I have spent hours making a steal inner barrel and shimming the tightbore with teflon tape to ensure it is true. It takes work you cant just install and go with long barrels they don't support there own weight and must be shimmed correctly to ensure they are flat. Otherwise it will bow between ends if not supported well. This is why shorter barrels seem more reliable as well, they have a better chance of being true and they support their own weight if they need to because the AEG does not. Another thing, if your AEG is weak and the barrel assembly is not free floated from a support hand or bipod then the barrel is going to move as the AEG fires, the heavier the spring the more it will rattle the AEG and barrel. To make an AEG accurate is serious work.

check out my DMR for the kinds of things you need, notice everything from the hop unit forward is free floated? See the steel barrel I had to make to support the 650mm tightbore? Its not install and shoot at this level.

Edited by ArmorerKen, 18 June 2009 - 06:05 PM.

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#36 Stealthmaster14

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Posted 18 June 2009 - 06:15 PM

How exactly do you know the bbs don't bounce in your barrel? (no disrespect or anything)

I would think it would take a while for the bb to settle in the barrel because the back spin the bucking applies would cause the bb to go upwards and hit the barrel. It would probably then hit the "bottom" of the barrel. I would think this would continue for a while, if not the whole time.
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Custom JG G36K-Madbull 6.03mm 363mm tightbore, Falcon 70 degree bucking, Deans, Guarder spring guide, Guarder SP110, Element POM bearing piston head, #14 O ring, longer air nozzle, SRC type 0 cylinder, dream army 7mm bushings, AOE adjusted
Youtube channel-http://www.youtube.com/user/Stealthmaster15?feature=mhum

Airsoft is pretend war, but for big boys

#37 ArmorerKen

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Posted 18 June 2009 - 06:59 PM

First of all I am only talking about high grade EXPENSIVE polished BB's. Not bio ammo. My choice is Marishin .36gm match grade BB's.

You need to consider the air is trying to escape around the BB and is at very high pressure, a polished BB and a true and smooth barrel allow the air to evenly try to escape around the entire sphere and center it in the barrel. I know mine don't because I can hit things far away over and over again and I can see the BB is doing the exact same thing every time.

I can't prove it to you without handing you the AEG and a clip and letting you have at it. But look at the quality of the upgrades and modifications I have done on that thing. If you don't believe then go get a tanaka pre JP ban with the PCS valve and upgrade an AEG like mine and mess with them for a few years. Shoot others AEG's, work at a field as a ref, and mess around with upgraded springers. Take on some work fixing and upgrading others AEG's. Then you will have your own conclusions just like I do.

The BB's from my AEG do not start to show variation until the wind effects them, which depends on the wind and the weight of the BB I am firing. I am talking about high grade ammo of course, if I throw a bag of rough bio ammo in a high cap and go full auto the shots show signs of hitting the barrel as the hop spin becomes inconsistent. I do not do this often as the bio ammo will leave residue in the barrel when it hits, requiring a cleaning. Firing bad ammo can and will hurt a tightbore barrel.
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#38 Stealthmaster14

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Posted 18 June 2009 - 07:21 PM

I'm not trying to call you a liar, I'm just trying to learn. :) Sorry if you took it that way.

Thanks for explaining it. a-thumbsup.gif

I'm using KSC and G&G .25s in my Edgi 6.01mm, they work pretty well. (definitely nowhere near as good as super expensive brands like SMGs and what not) I don't think have done any damage. a-shocked.gif
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Custom JG G36K-Madbull 6.03mm 363mm tightbore, Falcon 70 degree bucking, Deans, Guarder spring guide, Guarder SP110, Element POM bearing piston head, #14 O ring, longer air nozzle, SRC type 0 cylinder, dream army 7mm bushings, AOE adjusted
Youtube channel-http://www.youtube.com/user/Stealthmaster15?feature=mhum

Airsoft is pretend war, but for big boys

#39 MaruiMan9122

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Posted 19 June 2009 - 01:57 AM

I completely agree but doesn't seem sort of weird for people to start sniping with the MP5K? a-laugh.gif (Just an example)
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QUOTE (aznriptide859 @ Apr 6 2010, 08:39 PM) <{POST_SNAPBACK}>
KA has the "our-engineers-don't-know-how-to-use-rulers" syndrome.

#40 ArmorerKen

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Posted 19 June 2009 - 04:16 AM

No you did not come off as calling me a liar just as wanting to understand, I was just frustrated with my lack of handy video examples to post, im so lazy I should have a few but never want to bother filming AND upgrading.

the really annoying sniper wannabes are peeps with extended barrels in non blowback high flow pistols. basically a sniper, but not role playing so I say beat them with a hose and then send them back to the paintball field. this is mil-sim land get out with your cheesy tightbore mounted on a crossman pellet gun before I snap it over my knee!

I have seen that, tightbore bolt action loading upper receiver-esqe contraption with crossman pellet pistol based lower, frankin-gun. The thing was monstrously powerful and sooo ugly, bits of epoxy here and there, just a mess. I still have the nightmares...
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