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 SCRAMBLD 
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Joined: Jul 2005  NC, USA
 Posts: 729 Feedback: 100% (14) |
Posted: 1/7/2012 10:39:57 AM
THE IMAGE ABOVE IS A PAID ADVERTISEMENT My question is: How short can I make the barrel befor I have stability issues? I shoot this rifle mostly suppressed and I don't want to risk a baffle strike due to an unstable bullet. My can is an older reflex type and I'd like to shorten the bbl. to help with the weight and balance of the rifle. I'd like to shorten the bbl atleast 6 in. but I'm thinking 8 in. which with the can will make the overall length the same as it is now with just the 26 in. barrel and no suppressor. Total length is currently 56 .25 inches with the suppressor with a 6 in. bbl chop 50 in. overalll and with an 8 in. chop 48 in. overall Jason |
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eracer
Building up my immunity to Iocane...
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Posted: 1/7/2012 10:52:41 AM
Interesting. 1:14" twist is rather unusual for .308, isn't it?
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Posted: 1/7/2012 11:06:33 AM
Originally Posted By eracer:
Interesting. 1:14" twist is rather unusual for .308, isn't it? I would think so too. Might want to really pay attention to bullet weight or keep them slow with that twist. |
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Posted: 1/7/2012 11:09:33 AM
[Last Edit: 1/7/2012 11:11:06 AM by SCRAMBLD]
generally speaking yes, 1 in 14 is odd, In this ones case, The barrel is a pull off barrel from a Parker-Hale L81(m81) Target rifle.
Wiki-pedia claims it to be a 1 in 12 but my cleaning rod with a really tight patch shows a 1 in 14 I only shot 150 gr. at the time being I want to try some 168 smk's but havn't had the time for load development. Jason edited to add info |
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PropDoc
Get it at Adco.
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Joined: Oct 2006 OH, USA
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Posted: 1/8/2012 12:15:40 PM
Barrel length is not really a deciding factor on bullet stabilization. Barrel length is a deciding factor in bullet velocity. You should have no trouble cutting it to 18" or 20".
Note: Longer barrels do not make the rifle theoretically more "accurate", they raise the bullet velocity, thus getting it to the target faster. This, in turn, gives atmospheric forces (wind, heat, dust, etc) less time to affect bullet flight. So, a shorter barrel will need more "read" of those factors, to put the round on target, but it will still do the job. |
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Posted: 1/8/2012 12:38:27 PM
Prop doc,
Thank you for your help. Now I just need to come up with the funds for the chop. Jason |
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jestevens3
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Joined: Mar 2009 TX, USA
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Posted: 1/8/2012 1:12:35 PM
Originally Posted By PropDoc:
Barrel length is not really a deciding factor on bullet stabilization. Barrel length is a deciding factor in bullet velocity. You should have no trouble cutting it to 18" or 20".
Note: Longer barrels do not make the rifle theoretically more "accurate", they raise the bullet velocity, thus getting it to the target faster. This, in turn, gives atmospheric forces (wind, heat, dust, etc) less time to affect bullet flight. So, a shorter barrel will need more "read" of those factors, to put the round on target, but it will still do the job. Bullet velocity has an effect on spin rate and therefore stabilization. There is an interaction between bullet velocity and rate of twist. Cut the barrel too short, especially with 1:14 twist, and you will have stability issues due to the reduced velocity. Bullet weight, length, and center of mass also have an effect. |
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PropDoc
Get it at Adco.
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Posted: 1/8/2012 2:22:54 PM
Faster spin/velocity does not always mean more stable. Unless you build your own bullets, you will never know the Center of Mass, Center of Gravity, or Optimum spin rate. So, if it is nits we are picking, start your bullet mill. For the OP's question, it will not make an oz of difference.
ALL rifles are more accurate with one cartridge manufacturer over another (if you buy factory), or cartridge / load/ bullet set-up (if you load) over a different one. Using the SAME (apples to apples) load and bullet combo, will work better out of one barrel length/twist rate over the other, and it will NOT always be the longer barrel. You MUST test different set-ups to see what shoots best out of YOUR gun. So, although i agree 100% that there is a correlation between velocity and spin rate, that DOES NOT mean it is better. |
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eracer
Building up my immunity to Iocane...
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Joined: Dec 2002 FL, USA
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Posted: 1/9/2012 8:47:53 AM
Originally Posted By PropDoc: Barrel length is not really a deciding factor on bullet stabilization. Barrel length is a deciding factor in bullet velocity. You should have no trouble cutting it to 18" or 20". Note: Longer barrels do not make the rifle theoretically more "accurate", they raise the bullet velocity, thus getting it to the target faster. This, in turn, gives atmospheric forces (wind, heat, dust, etc) less time to affect bullet flight. So, a shorter barrel will need more "read" of those factors, to put the round on target, but it will still do the job. Barrel length also affects accuracy by changing barrel harmonics, yes? So with a given bullet weight/velocity, accuracy (and precision...) will be affected, yes? Does twist rate affect stabilization? If so, can't a barrel be 'too short' for a given twist by not allowing the bullet to develop enough spin (due to lack of velocity?) I'm not talking about the OP's situation, rather, I'm just thinking theoretically. What if we tried to fire a .308 220 gr. SMK out of a 6" barrel with 1 in 14 twist? Or 1 in 20 twist? |
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PropDoc
Get it at Adco.
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Posted: 1/10/2012 5:11:45 PM
Originally Posted By eracer:
Originally Posted By PropDoc:
Barrel length is not really a deciding factor on bullet stabilization. Barrel length is a deciding factor in bullet velocity. You should have no trouble cutting it to 18" or 20".
Note: Longer barrels do not make the rifle theoretically more "accurate", they raise the bullet velocity, thus getting it to the target faster. This, in turn, gives atmospheric forces (wind, heat, dust, etc) less time to affect bullet flight. So, a shorter barrel will need more "read" of those factors, to put the round on target, but it will still do the job. Barrel length also affects accuracy by changing barrel harmonics, yes? No. Just because it is longer, doesn't mean the harmonics are better. Harmonics are a basic factor of barrel manufacture, not length. So with a given bullet weight/velocity, accuracy (and precision...) will be affected, yes? Again, longer does not mean better. With a given bullet, a short barrel may shoot better it better than the longer, OR the longer may shoot it better. Only way to know is shoot it. Does twist rate affect stabilization? If so, can't a barrel be 'too short' for a given twist by not allowing the bullet to develop enough spin (due to lack of velocity?) I'm not talking about the OP's situation, rather, I'm just thinking theoretically. What if we tried to fire a .308 220 gr. SMK out of a 6" barrel with 1 in 14 twist? Or 1 in 20 twist? Well, a bullet that heavy needs a much faster twist rate (1:10 is slow for that) so neither would shoot it well, but the 1:14 would most likely shoot it better. It basically comes down to, longer barrels will shoot some ammo better than short, as will short shoot better than long with others. You will probably not get the best performance out of a short barrel, that the long barrel shoots best, and vica-versa.
Note: A 6" barrel on a .308 would be a waste of time and effort.  |
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Posted: 1/10/2012 8:10:39 PM
I think you will find that barrel length can effect bullet stabilazition with a longer barrel offering more velocity. This has already been pointed out and is a fact that a faster bullet in a slow twist can straighten out a marginal match of twist and bullet type.
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PropDoc
Get it at Adco.
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Posted: 1/10/2012 10:14:54 PM
Yet again, faster is not always better.
If you take a light bullet, and twist it too fast, the bullet will disintegrate part way down the range, with NO target hit. Put a heavy bullet in a load and barrel that generates TOO MUCH twist, it will fly apart as well. I can show you, that a 20" barrel, with a given ammo set-up, will out shoot a 26" barrel with the same load.......AND vise versa. I AGREE, some loads work better in a longer barrel, but not ALL loads, nor do they ALL need it, you have to find the load that works best. The SAME goes for the shorter barrels. Please stop saying a longer barrel is ALWAYS more accurate, because it is just NOT true.  |
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benw8887
Severed heads equal open minds!
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Joined: Dec 2009 NM, USA
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Posted: 1/10/2012 10:55:39 PM
I've got a Savage model 10 (.308) with a bull barrel. It's has a 22 inch barrel, I want to have it cut to 18 inches, how much would that cost at Adco PropDoc?
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PropDoc
Get it at Adco.
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Posted: 1/11/2012 6:14:04 AM
Originally Posted By benw8887:
I've got a Savage model 10 (.308) with a bull barrel. It's has a 22 inch barrel, I want to have it cut to 18 inches, how much would that cost at Adco PropDoc? Bolt gun Cut/thread/crown runs $140 plus actual shipping.
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eracer
Building up my immunity to Iocane...
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Posted: 1/11/2012 10:01:00 AM
Originally Posted By PropDoc: Note: A 6" barrel on a .308 would be a waste of time and effort. Yeah but it would make a really cool flamethrower! |
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benw8887
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Posted: 1/11/2012 11:14:42 AM
Originally Posted By PropDoc:
Originally Posted By benw8887:
I've got a Savage model 10 (.308) with a bull barrel. It's has a 22 inch barrel, I want to have it cut to 18 inches, how much would that cost at Adco PropDoc? Bolt gun Cut/thread/crown runs $140 plus actual shipping.
Thank you sir. Do you need the whole rifle or just the barreled action? What muzzle device would you recommend for the .308? Originally Posted By eracer:
Originally Posted By PropDoc:
Note: A 6" barrel on a .308 would be a waste of time and effort. Yeah but it would make a really cool flamethrower! That's funny!  |
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PropDoc
Get it at Adco.
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Joined: Oct 2006 OH, USA
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Posted: 1/11/2012 3:52:51 PM
Barreled action.
Ops Inc 3rd model.
Actually, think the BattleComp BABC works well, looks cool too. |
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