shortening the barrel

DWFan · 04-19-2008, 07:47 AM

Does shortening the barrel on a pump pneumatic rifle have the same effect on velocity as a centerfire? Is there an "ideal" barrel length for a .22 caliber?

jaybo · 04-19-2008, 08:33 AM

As you are not "waiting" for powder burning to burn completley to achieve maximum velocity, and the total friction of traveling through a shorter barrel, would make it seem that just the opposite would be true and you might actually gain velocity. There is likely a point of deminishing returns, though.

Nothing to base this idea on, just a guess that could be wrong.

Sooner Shooter · 04-20-2008, 09:02 PM

I'm in agreement with Jaybo. You have a certain amount of air that will come out in one quick burst. It will occupy the hollow part in the pellet then start the push of the pellet. Wasted energy will find the grooves in the barrel. I would think stabilization of the pellet will be the issue with shortening of the barrel. I never see air hand guns with velocities like the rifles. Like Jaybo, just a guess! Where's Binford? He'll know!

perdidochas · 04-22-2008, 03:54 PM

Quote:

Originally Posted by Sooner Shooter

I'm in agreement with Jaybo. You have a certain amount of air that will come out in one quick burst. It will occupy the hollow part in the pellet then start the push of the pellet. Wasted energy will find the grooves in the barrel. I would think stabilization of the pellet will be the issue with shortening of the barrel. I never see air hand guns with velocities like the rifles. Like Jaybo, just a guess! Where's Binford? He'll know!

This link seems to indicate otherwise. The longer the length, the higher the velocity.

Air guns - Pyramyd Air Report: Is airgun barrel length important?

binfordw · 04-22-2008, 05:24 PM

I'm no expert on custom airguns and such,
From what I understand, there is a point of diminishing returns on barrel length. Dennis Quackenbush has some interesting articles on custom airgun making, some of which I recall reading about barrels and length. Think they even did a test.

Shorter barrels definetely start to "waste" available air, and velocities won't be as high. Longer, and friction would start to take over.

andrew cochran · 04-22-2008, 06:00 PM

Quote:

Originally Posted by binfordw

I'm no expert on custom airguns and such,
From what I understand, there is a point of diminishing returns on barrel length. Dennis Quackenbush has some interesting articles on custom airgun making, some of which I recall reading about barrels and length. Think they even did a test.

Shorter barrels definetely start to "waste" available air, and velocities won't be as high. Longer, and friction would start to take over.

So ya got to have it inbetween.

Sooner Shooter · 04-22-2008, 06:47 PM

Quote:

Originally Posted by perdidochas

This link seems to indicate otherwise. The longer the length, the higher the velocity.

Air guns - Pyramyd Air Report: Is airgun barrel length important?

I'm glad that wasn't a test! My guesses weren't very good. Thanks for the article. This if another story but it reminds me of how my thinking was always wrong about the length of shotgun barrels. I always thought that a longer barrel would throw a tighter pattern but I believe Remington proved that there would be no difference or negligible difference down to about 16 or 20 inches. They determined the only thing that mattered was the diameter of the bore at the muzzle.

jaybo · 04-22-2008, 06:48 PM

Perdidochas,

Thanks for the link, quite educational. I did notice that "today's spring-piston guns probably don't use more than the first 10 inches of barrel for top velocity." That was somewhat my thinking as I have a spring-piston rifle. It's also interesting that length doesn't affect accuracy.

Never too old to learn something new.

04-19-2008, 07:47 AM	#1
DWFan Senior Member Join Date: Feb 2008 Location: N. Texas Posts: 696 Blog Entries: 2	shortening the barrel Does shortening the barrel on a pump pneumatic rifle have the same effect on velocity as a centerfire? Is there an "ideal" barrel length for a .22 caliber?

04-20-2008, 09:02 PM	#3
Sooner Shooter Senior Member Join Date: Feb 2008 Location: Oklahoma Posts: 614	I'm in agreement with Jaybo. You have a certain amount of air that will come out in one quick burst. It will occupy the hollow part in the pellet then start the push of the pellet. Wasted energy will find the grooves in the barrel. I would think stabilization of the pellet will be the issue with shortening of the barrel. I never see air hand guns with velocities like the rifles. Like Jaybo, just a guess! Where's Binford? He'll know! __________________ Save the drama for your mama!

04-19-2008, 08:33 AM	#2
jaybo Member Join Date: Mar 2002 Location: Goshen, IN Posts: 48	As you are not "waiting" for powder burning to burn completley to achieve maximum velocity, and the total friction of traveling through a shorter barrel, would make it seem that just the opposite would be true and you might actually gain velocity. There is likely a point of deminishing returns, though. Nothing to base this idea on, just a guess that could be wrong.

04-22-2008, 05:24 PM	#5
binfordw Member Join Date: Oct 2007 Posts: 57	I'm no expert on custom airguns and such, From what I understand, there is a point of diminishing returns on barrel length. Dennis Quackenbush has some interesting articles on custom airgun making, some of which I recall reading about barrels and length. Think they even did a test. Shorter barrels definetely start to "waste" available air, and velocities won't be as high. Longer, and friction would start to take over.

04-22-2008, 06:48 PM	#8
jaybo Member Join Date: Mar 2002 Location: Goshen, IN Posts: 48	Perdidochas, Thanks for the link, quite educational. I did notice that "today's spring-piston guns probably don't use more than the first 10 inches of barrel for top velocity." That was somewhat my thinking as I have a spring-piston rifle. It's also interesting that length doesn't affect accuracy. Never too old to learn something new.