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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/13/2008 at 17:50
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After shooting some 62Gr Federal soft points out of a 20" 1-9" twist Barrel. A couple of the shots appeared to have some wobble. Evidenced by an elongated hole. Could this have been caused by 20 mph winds from behind or does there need to be more twist for this heavy of a bullet? I realise these are not the best bullets but they were all that was avaliable at the time.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/13/2008 at 18:16
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 The wind may have rippled the target paper as the bullet passed through it.
 My 1-9 Bushmaster stabilizes everthing up to and including the 75 gr. Hornady HPBT Match.
 It does not handle the 75 gr. AMAX.
  Every barrel acts differently though.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/13/2008 at 18:48
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This is a new rifle and It has only had 15 rounds. I didn't notice it until after I posted ithe target here. The two oval shots were not fliers, but it was only 5 shot target. Guess I am worring about nothing. Barrel twist has never been considered before being here.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/13/2008 at 23:19
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 Try out some different loads at various distances, and see how they group. Unless you have a bad barrel, it will probably shoot just fine.

 I'm assuming it is an AR?  What brand?

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/14/2008 at 02:32
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A 1 in 9" twist is tight. It should stabilize even heavier bullets. A .308 caliber runs a 1 in 10 twist and stabilizes up to 220gr. Mostly the smaller calibers run with a 1;12 or even 1;14. So I cannot see that the 1;9 can be a problem. Look elsewhere.
Barrel length has no effect on the twist rate.


Edited by 8shots - March/14/2008 at 02:33
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/14/2008 at 19:11
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Originally posted by 8shots 8shots wrote:

A 1 in 9" twist is tight. It should stabilize even heavier bullets. A .308 caliber runs a 1 in 10 twist and stabilizes up to 220gr. Mostly the smaller calibers run with a 1;12 or even 1;14. So I cannot see that the 1;9 can be a problem. Look elsewhere.
Barrel length has no effect on the twist rate.
 
 Well ol' Buddy, I'm gonna call you out on that one, but only because I'm in an ornery mood!
 Technically, you're right, of course.
There are situations, however, wherein a bullet driven through a barrel of a given twist rate will not "go to sleep" unless it is driven at a velocity above a certain level.
 A 26 inch barrel may allow a handloader to achieve that velocity where a 20 inch tube may not allow him to do that within safe pressure parameters, with faster-burning propellents even though the twist may be the same rate in both barrels.
 Not really arguing, just making an observation...Cool
 
edited for spelling error.


Edited by RONK - March/14/2008 at 19:13
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/14/2008 at 20:34
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I see no reason that a 1 in 9 twist would not stabilize a 62gr. bullit in 223. If I suspected the barrel I would start with the crown. It may be damaged or uneven.Was it a clean bore with no oil in it? Next I would look at the ammo, or really, try different ammo. There could any number of things that could cause the bullit to keyhole, but a 1 in 9 twist is almost ideal for the 62gr. IMHO
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/15/2008 at 09:22
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 have you checked the velocity yet, they may be just short -- before precession http://bryanlitz.bravehost.com/EpSwerv.html
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/15/2008 at 21:13
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We are talking about a Rock River ar15 EOP varmint 20" stainless. I have not yet had a chance to do much of anything with it This is the target I was speaking of below. The target was taped on all 4 sides so it did not blow in the heavy wind. These were American Eagle soft points. 62Gr Maybe I shot 6 times instead of 5 It almost looks like it, the three grouped together are not round. I need to go back to the range to test and finish breaking in the barrel before I get anything started on here. So far all of my reloading on .223 has been for Remington 700vsfl with 26 " barrel. I have never had an AR so  don't know where to start for the best results. I know that a faster powder will probably be need than in the Remington.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/16/2008 at 09:48
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looks to me the entire target could have been slightly tilted to the left-- was the target backing made of anything that could fragment easily? 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/16/2008 at 13:55
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 I see what looks to be a nice six-shot group.  I really wouldn't worry about it at all.
 Those are not Match-grade bullets anyway. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/17/2008 at 03:01
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Originally posted by RONK RONK wrote:

Originally posted by 8shots 8shots wrote:

A 1 in 9" twist is tight. It should stabilize even heavier bullets. A .308 caliber runs a 1 in 10 twist and stabilizes up to 220gr. Mostly the smaller calibers run with a 1;12 or even 1;14. So I cannot see that the 1;9 can be a problem. Look elsewhere.
Barrel length has no effect on the twist rate.
 
 Well ol' Buddy, I'm gonna call you out on that one, but only because I'm in an ornery mood!
 Technically, you're right, of course.
There are situations, however, wherein a bullet driven through a barrel of a given twist rate will not "go to sleep" unless it is driven at a velocity above a certain level.
 A 26 inch barrel may allow a handloader to achieve that velocity where a 20 inch tube may not allow him to do that within safe pressure parameters, with faster-burning propellents even though the twist may be the same rate in both barrels.
 Not really arguing, just making an observation...Cool
 
edited for spelling error.
 
Ronk, take a look at this site:http: www.accuratereloading.com/223sb.html
 
Quite correct a shorter barrel requires more powder to maintain the same velocity. The point I was trying to make is that because this is a 20 inch barrel and not the standard 24 inch barrel, some readers may think that the shorter barrel is the cause of the bullets key-holing. In other words the short barrel is not spinning the bullet fast enough and thus not stabilizing. My point is that a bullet need not travel a minimum of X inches before the spin will stabilize it, but rather it must reach a certain velocity.
A very short barrel as in a pistol, will still stabilize a bullet at the correct velocity.
Whether the rifle or pistol is capable of giving that velocity is another discussion.
A short barrel can in fact be as accurate as a long barrel. As the barrel is shortened, so it stiffens up because the thickness to length ratio is improved. Alternatively, the thicker the same lenth barrel, the more accurate it becomes
 
 
 


Edited by 8shots - March/17/2008 at 03:08
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/17/2008 at 18:33
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 I have seen that before, 8-shots. accuratereloading.com is a very interesting place. Great hunting video clips, too! The cut-down Sako was an interesting and expensive experiment, but money means NOTHING to those folks!
 
 I agree with your other observations. too
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