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shlunka

Barrel length and it's effect on accuracy and range

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I would like to saw off some of the barrel on my L-96, but I was wondering how much could I cut without a noticeable decrease in range and accuracy. I'm doing this for a scout rifle project.

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I would like to saw off some of the barrel on my L-96, but I was wondering how much could I cut without a noticeable decrease in range and accuracy. I'm doing this for a scout rifle project.

 

It WILL.

Unless the barrel length that you currently have is too long, which I doubt it....

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It WILL.

But not by much, 90% of the range and accuracy you get will be from a good hop up and good bbs. Just be sure you don't leave any burs in the barrel itself, you sill want it to be smooth. It would also be very good to have a good crowning at the end of your barrel to ensure proper air flow around the bb.

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But not by much, 90% of the range and accuracy you get will be from a good hop up and good bbs. Just be sure you don't leave any burs in the barrel itself, you sill want it to be smooth. It would also be very good to have a good crowning at the end of your barrel to ensure proper air flow around the bb.

So would 6-8" off do much?

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I have had barrels in my rifles that were 4-6 inches long. And I really never saw that much decreas in accuracy. Like star said above, it is all about your hop up.

 

Heck my L96 that I am working on is soon going to get cut down from 500mm down to 280mm. Now becuase the hop up is so nice on this rifle, I am not worried about it. And if you are planning on using the rifle as a scout rifle anyway, you shouldn't be taking shots much longer than an AEG would anyway.

 

But again like star said, just make sure you take your time and do it correctly. I usually use a pipe cutter, and use very VERY little pressure each pass. Then put the barrel in my drill press and make a nice crown on the barrel. Just make sure you take care of all the burrs and anything that isn't supose to be there. Just take your time and plan it out and you will be fine.

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You will definitely notice a decrease in range due to a decrease in power. The power behind the BB will decrease substantially as the volume will be reduced for the cylinder/piston air to pressurize into.

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Like they said, barrel length isn't the issue. My WE PDW with a 9" barrel gets more range than my Ares AW-338, and they both shoot about the same power. Used Bioval .30's in the test, too. PDW is using the stock hop, and the Ares is using a Prommy soft. If I could, I would make my PDW a sniper rifle, but the barrel length is way too short. Plus, the FPS would be up to like 700-800, if I made the barrel a 650.

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Like they said, barrel length isn't the issue. My WE PDW with a 9" barrel gets more range than my Ares AW-338, and they both shoot about the same power. Used Bioval .30's in the test, too. PDW is using the stock hop, and the Ares is using a Prommy soft. If I could, I would make my PDW a sniper rifle, but the barrel length is way too short. Plus, the FPS would be up to like 700-800, if I made the barrel a 650.

 

um....there's no way that the FPS can be 700~800 with 650mm....

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It can, the longer the barrel, the more FPS GBBs get.

 

um...you won't be able the achieve 700~800fps just with a longer barrel....

The relationship between FPS and barrel length is not proportional......

Edited by EDI 1st

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Yes you can get some FPS gain from a longer tighter barrer in a GBBR, but nothing like you are thinking though. You will get a boost, but nothing that high.

 

But back on topic.....

 

I just replaced my 500mm barrel with a 280mm barrel in my TM L96, and guess what........ same accuracy, and dang near the same range. Just need to play with the hop a little bit when you get to a smaller barrel, but as long as you have a good hop, then you are good to go.

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I know I'm probably just repeating what was already said, but here goes. This past weekend at Northern Lights, I was fielding the Polartstar PR-15. Needless to say, when we got it in the mail the few weeks before, it was apart and being messed with in under 5 minutes haha. We actually got more range out of a PDI 6.05 363mm than we did with a PDI 6.05 509mm. Now, this may be relative to the chemistry of the gun itself, but I've seen pretty much identical results between two different lengths in my rifles too.

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um...you won't be able the achieve 700~800fps just with a longer barrel....

The relationship between FPS and barrel length is not proportional......

Absolutely wrong, while it's true that barrel length will not give you that much velocity it does have an effect. Think about it for a while, once the bb is a few inches past the end of the barrel it starts dropping in fps right? and while it is in the barrel the gas from either CO2, green gas or the compression from a spring piston is pushing the bb down the barrel causing the bb to speed up correct? So if the barrel is longer the gas will have a larger space to expand and push the bb up to it's max velocity. This remains true until the barrel is so long that the gas has fully expanded before the bb reaches the end of the barrel, then the barrel actually slows it down.

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I would like to saw off some of the barrel on my L-96, but I was wondering how much could I cut without a noticeable decrease in range and accuracy. I'm doing this for a scout rifle project.

It's pretty simple: Barrel length has NO effect on range. Power and hop up are the two most significant factors in range, shortening the barrel will reduce power by a good amount but if you have a good hop up system you shouldn't notice a big drop off in range. Plus if your doing this for a scout rifle project than odds are your furthest shots will be at only 40-50 yards so range shouldn't be a problem almost no matter what.

 

As far as accuracy goes, shortening the barrel will have a significant effect on that. As long as you don't bend or damage the barrel in any way when cutting it, the accuracy will not be effected too bad.

 

I agree with woogie man 100%. Crowning the barrel is extremely important so make sure you have the proper tools before you start this part of the procedure.

 

On how much to cut off I can't help you with that, I'd need to go to your field or where ever you play to know how tight the woods, buildings, streets or whatever. I'd say take the absolute least amount off you can. Try it and if you keep getting caught in the brush then go back and take a couple more inches off. Nothing is worse than having to buy a new barrel because you took too much off and now the rifle is just unshootable :(

 

Cheers

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Absolutely wrong, while it's true that barrel length will not give you that much velocity it does have an effect. Think about it for a while, once the bb is a few inches past the end of the barrel it starts dropping in fps right? and while it is in the barrel the gas from either CO2, green gas or the compression from a spring piston is pushing the bb down the barrel causing the bb to speed up correct? So if the barrel is longer the gas will have a larger space to expand and push the bb up to it's max velocity. This remains true until the barrel is so long that the gas has fully expanded before the bb reaches the end of the barrel, then the barrel actually slows it down.

 

um....do you even realize that you just said what I said?

 

And still, no chrono, no proof.

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It's pretty simple: Barrel length has NO effect on range. Power and hop up are the two most significant factors in range, shortening the barrel will reduce power by a good amount but if you have a good hop up system you shouldn't notice a big drop off in range. Plus if your doing this for a scout rifle project than odds are your furthest shots will be at only 40-50 yards so range shouldn't be a problem almost no matter what.

 

As far as accuracy goes, shortening the barrel will have a significant effect on that. As long as you don't bend or damage the barrel in any way when cutting it, the accuracy will not be effected too bad.

 

I agree with woogie man 100%. Crowning the barrel is extremely important so make sure you have the proper tools before you start this part of the procedure.

 

On how much to cut off I can't help you with that, I'd need to go to your field or where ever you play to know how tight the woods, buildings, streets or whatever. I'd say take the absolute least amount off you can. Try it and if you keep getting caught in the brush then go back and take a couple more inches off. Nothing is worse than having to buy a new barrel because you took too much off and now the rifle is just unshootable :(

 

Cheers

I don't play at a field, I play on 100-300 acres of family owned woodlands. But I needed the shorter barrel to maneuver through thick brush and thorn bushes, and the stock barrel length makes it very difficult to do any movement without stirring up the surrounding brush. Engagements usually range between 50-60 yards.

 

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I don't play at a field, I play on 100-300 acres of family owned woodlands. But I needed the shorter barrel to maneuver through thick brush and thorn bushes, and the stock barrel length makes it very difficult to do any movement without stirring up the surrounding brush. Engagements usually range between 50-60 yards.

I'd take no more than 4 inches off. That should be enough to get you through the brush but if it's not, just do the procedure again. My biggest concern when I'm modifying a rifle is maintaining accuracy and shortening it any more than that would have too much effect on accuracy IMO. Every rifle is different so do an initial cut and hopefully you'll get lucky and it'll turn out perfect. If not, buy the parts and start over lol. Good Luck

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um....do you even realize that you just said what I said?

 

And still, no chrono, no proof.

The relationship between velocity and barrel length is proportional... This has been proven with physics, fire arms, paintball guns, pellet guns, and now in airsoft. Do your research, I'm sure someone has some chrony numbers for you. I know in my paintball days my team got a penalty because when someone on my team switched to a 16" barrel instead of a 12" barrel between games, his gun shot over the 300 fps limit. With the 12" barrel he shot 290 fps, with the 16" barrel he shot 310 fps.

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The relationship between velocity and barrel length is proportional... This has been proven with physics, fire arms, paintball guns, pellet guns, and now in airsoft. Do your research, I'm sure someone has some chrony numbers for you. I know in my paintball days my team got a penalty because when someone on my team switched to a 16" barrel instead of a 12" barrel between games, his gun shot over the 300 fps limit. With the 12" barrel he shot 290 fps, with the 16" barrel he shot 310 fps.

 

Sorry, but I seriously lol'd hard.

Cause if what you are saying is true, then we should be expecting a BB shooting over the speed of sound if we get a barrel that's long enough.

And even PASS the speed of light, which is impossible as the speed limit of the universe IS the speed of light.

 

And I can guarantee you that the same gun that you are talking about won't bee shooting at 510fps with a 56" barrel.

 

Somebody needs to retake basic physics.....

Energy is "depleted" as it is transferred from the expansion of the gas to the BB.

Once the energy is equalized, the BB won't accelerate anymore.

"Equilibrium"

That was not even college Physics....more like high school physics...

Edited by EDI 1st

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Are you taking "proportional" to mean "linearly proportional"? Within certain boundaries, and within reasonable airsoft usage, there does seem to be a positive correlation between barrel length and muzzle energy in many gas guns.

 

And, you really need to get your own terminology correct. Once the energy from the gas has "equalized" as you said, the BB will still accelerate. That is a fact.

 

Also, if you really want to argue using physics, the speed of sound isn't constant, therefore, yes, you can shoot a BB faster than the speed of sound. State your assumptions, then make your claims. Don't assume everyone else uses the same assumptions as you do.

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Will still, what headshot is saying is that as long as the BB is in the barrel, it'll accelerate no matter how long the barrel is.

 

And on the equilibrium, the BB will still accelerate after the gas has completely expanded and transfer the energy to the BB?!?!

 

Speed of sound in air, ground level.

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Maybe he left out a possibly implied "within reason" or "within common lengths," similar to how you left out some of what you were obviously implying, but neglected to actually say.

 

Yep, the BB will accelerate. That value of acceleration may be negative, but it will still have acceleration, unless of course we leave this universe for one with a massless firing system (because the gravitational forces will exist in our own) and run the test in a vacuum. That is also basic high school physics, since you were talking about it. "Acceleration" a perfectly acceptable physics term, though maybe not as common for colloquial usage when referring to negative values.

 

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Sorry, but I seriously lol'd hard.

Cause if what you are saying is true, then we should be expecting a BB shooting over the speed of sound if we get a barrel that's long enough.

And even PASS the speed of light, which is impossible as the speed limit of the universe IS the speed of light.

 

And I can guarantee you that the same gun that you are talking about won't bee shooting at 510fps with a 56" barrel.

 

Somebody needs to retake basic physics.....

Energy is "depleted" as it is transferred from the expansion of the gas to the BB.

Once the energy is equalized, the BB won't accelerate anymore.

"Equilibrium"

That was not even college Physics....more like high school physics...

I understand that perfectly. If a rifle has a 350mm barrel than odds are it's powerful enough to push the bb down the barrel and when it gets to the end there is a loud pop due to escaping gasses. If you lengthen the barrel to 400mm there will be an increase in velocity and a decrease in noise. Thats because when the bb gets to the end there is less pressure behind the bb, but there is still pressure! The velocity will keep increasing inside the barrel until it reaches the end because the gasses aren't pushing it anymore, a longer barrel = more time for the gas to expand and push the bb faster. True, if the barrel is too long the pressure will equalize but, the barrel would have to be so long it would be impractical. What I meant is FPS and barrel length are proportional to a point when the pressure equalizes.

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I understand that perfectly. If a rifle has a 350mm barrel than odds are it's powerful enough to push the bb down the barrel and when it gets to the end there is a loud pop due to escaping gasses. If you lengthen the barrel to 400mm there will be an increase in velocity and a decrease in noise. Thats because when the bb gets to the end there is less pressure behind the bb, but there is still pressure! The velocity will keep increasing inside the barrel until it reaches the end because the gasses aren't pushing it anymore, a longer barrel = more time for the gas to expand and push the bb faster. True, if the barrel is too long the pressure will equalize but, the barrel would have to be so long it would be impractical. What I meant is FPS and barrel length are proportional to a point when the pressure equalizes.

This is my personal experience talking, not a physics class. I've seen the results of a barrel being too long, drag and vacuum become a factor, but the pressure a PB gun, spring rifle, or gas gun are all at about 200psi or higher. That means the barrel would be outrageously long before you saw equalizing pressure.

 

 

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Maybe he left out a possibly implied "within reason" or "within common lengths," similar to how you left out some of what you were obviously implying, but neglected to actually say.

 

Yep, the BB will accelerate. That value of acceleration may be negative, but it will still have acceleration, unless of course we leave this universe for one with a massless firing system (because the gravitational forces will exist in our own) and run the test in a vacuum. That is also basic high school physics, since you were talking about it. "Acceleration" a perfectly acceptable physics term, though maybe not as common for colloquial usage when referring to negative values.

 

Oh yea lol, forgot that change of speed and direction = acceleration XD

But it won't speed up in the direction that it is moving.

 

And Headshot, you said the same thing that I said even though you said it was wrong.

Edited by EDI 1st

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Oh yea lol, forgot that change of speed and direction = acceleration XD

But it won't speed up in the direction that it is moving.

 

And Headshot, you said the same thing that I said even though you said it was wrong.

Maybe I just explained it badly. The point is if you buy a slightly longer barrel for your rifle you will get a slightly higher velocity. If you buy an outrageously long barrel you will get a lower velocity because the gas will expand and then there will be drag slowing the bb down. Sorry if I misunderstood and restated what you said.

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