5.56-223 from 10.5 inch Barel

carlchevalier said:
I you read this thread, The original Question pertained to weight and accuracy.

I dont think anybody really answered my original question. I think a lot of you people on this thread like to hear their own opinions as useless as they are.

Will a 1 in 7 twist barrel produce the same accuracy with a 55 gr bullet than a heavier projectile or not?
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Yes.
With quality bullets.
 
THANK YOU!!!! tiriaq and reddot. I dont reload (will soon) so who makes good accurate bullets in different weights so I can test that theory for myself and where do I buy them.
 
As an experiment, buy some factory sporting ammunition with 55s. Try them side by side with factory 69s.
This should give you an idea of what you can expect with handloads. What works in one barrel might not in another.
I have two AR barrels, one 1:12, the other 1:8. Both are accurate with 55 ball. The 1:8 will also shoot bullets through 77gr just fine. Would probably shoot 80s, but that would require single loading.
The heavier bullets are intended to extend the range of the .223, improve performance in the wind. They are not necessarily any more inherently accurate than lighter bullets, given equal quality.
The 1:7 barrel was developed to allow the long tracer bullet to be used, not to enhance the performance of any conventional bullet. It is a quicker twist than needed. But there is no reason though that decent ammunition should not shoot very well indeed.
 
carlchevalier said:
I you read this thread, The original Question pertained to weight and accuracy.

I dont think anybody really answered my original question. I think a lot of you people on this thread like to hear their own opinions as useless as they are.

Will a 1 in 7 twist barrel produce the same accuracy with a 55 gr bullet than a heavier projectile or not?
Click to expand...

This will depend on range and quality of the ammunition.

To 100m 55gr ammo can produce submoa results.

Interesting enough I have gotten submoa perfromace from some 55gr Wolf ammo out of our SR15E3's but I would not consider that to be standard.

Also some barrels from the same manufacturers will like some ammuntion types better than others -- Fleet Yaw

I've been on the range all this am with 11.5" guns - some like 70gr, some like 55gr, some like 77gr.

The larger amount of barrels you have to shoot and the more accurately you can track the data will give you a better idea on how the barrels will perform, but once again, its an average, not specific to YOUR barrel.
 
Will a 1 in 7 twist barrel produce the same accuracy with a 55 gr bullet than a heavier projectile or not?
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Conventional wisdom says a fast twist barrel will not shoot lightweight bullets well. My experience is this is not true. At least some fast twist barrels will shoot lightweight bullets very well. But that doesn't mean they all will and as mentioned above probably the quality of the bullet is a factor as well.

What all that means is you have to try it in your rifle.
 
When the US first tested the M16A2 in the easrly 80's, they foundd that the 1/7 will shoot slightly more accurately with the M193 ammo than the then new SS109 bullets within 200m.

I am sure KevinB can ask Dave about it at work.
 
Very true, a lot of erroneous info gets passed on about M193 and 1:7 barrels.

You should listen to Dave rant about some of the "conventional wisdom" being offered as gospel, he still has REAMS of test data from Colt and the USMC on this, and other items, and its amazing to see how some folk lore being spouted by a writer (read: HACK) will get taken as coming off the mount...
 
I tried the 55 grains and never got good accuracy with them than with heavier bullet. I tried so many powder / set up and factory ammo ( Black Hills Match - Hornady Match also ) that my logs are 1 inches thick !! Whatever - most 55 tried were reloaded with service grade FMJ's and the 68 grains were premium bullet. In a COLT Match HBAR with a 20'' barrel ( purchased new ) it was really bad - 3 to 5 inches group at 100 yards with the 55 grains. So with the 1/7 twist - my experimentation is over :) Since then I sold the Colt and now have a Bushmaster Varminter 24 inches tube with 1/9 twist and will never go back to 1/7.- I also stick to 68 /75 grains match bullet (.75 to 1 inches group easily and rare .50 groups ).

Many guys report good accuracy with the 1/7 and 55 grains but I never seen any at our range with an ''accurate'' combination. Range in the 2 to 3 inches group with flyer opening to 4 inches seem the best for 10 rounds for those -but most of the time worse.
 
X-man said:
Beyond that, I haven't experimented as I haven't been in a position to renew my provinical rifle association membership and try shooting at long range at the DND range in my area.
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I hope to hear that changes for Spring 2010.

AEIs Gun Camp is 10 minutes away from said range, new and better for 2010. :)
 
Conventional wisdom says a fast twist barrel will not shoot lightweight bullets well. My experience is this is not true. At least some fast twist barrels will shoot lightweight bullets very well. But that doesn't mean they all will and as mentioned above probably the quality of the bullet is a factor as well.
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+1

Janeau, I have also heard similar stories before.
My own results are mixed.
But there is no reason though that decent ammunition should not shoot very well indeed.
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My 2c, 7" twist seems less forgiving to lower quality light bullets. ^flyers. But some light bullets (generally match ammo) seem to shoot through anything.

Generally, I'd like a 8.5". But frankly, don't really care that much either way. Once I have a carbine zeroed, I don't spend a lot of time trying to shoot benchrest groups, but do check things out occasionally. They all seem to hit their targets if I do my part.

I'd wager $2 on a 1/9 over a 1/7 with 55gn FMJ-BT. ;)
 
We re finally getting somewhere!!! many thanks to all you knowlegeable gents... who finally came out of the woodwork.
The only problem now is finding decent commercial ammo to do this
 
Agreed

dangertree said:
+1

Janeau, I have also heard similar stories before.
My own results are mixed.
My 2c, 7" twist seems less forgiving to lower quality light bullets. ^flyers. But some light bullets (generally match ammo) seem to shoot through anything.

Generally, I'd like a 8.5". But frankly, don't really care that much either way. Once I have a carbine zeroed, I don't spend a lot of time trying to shoot benchrest groups, but do check things out occasionally. They all seem to hit their targets if I do my part.

I'd wager $2 on a 1/9 over a 1/7 with 55gn FMJ-BT. ;)
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My 10 1/2 9 twist shoots the 55's much more accurately - amazingly many 1/4 ito 1/2 inch 3 rd 200 yd groups (zero wind only- a little gust - 3 inches or more)
 
KevinB said:
FYI a 3 rd group is meaningless.

10 rds groups or 4x5 rd groups that are avg'd, are the really only way to test for accuracy.
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Agreed but the test was not for accuracy - it was to compare 69 grainers with 55's - the 69 grain 3 rd groups were much larger.
 
Still a 3rd group is meaningless.

You did not have a valid sample size for either of the rounds.

Years ago I shot 40gr Federal Blitz, 55gr M193, IVI C77 and Federal 69gr from a 4 barrels
14.5 1:9 BM
14.5 1:7 Diemaco
20" 1:9 BM
20" 1:7 Colt

At 100m the 40gr federal Blitz shot best from the 20" Colt, the rounds blew apart in the 14.5" Diemaco, the 'conventional wisdom" was that the rounds where overstabilized in the 1:7 and could not handle the rotational forces.
What really was happening is the rifling of the Diemaco barrel was sharper and the bullet jacket (as thin as it is) was basically being prefragmented at the pressures in that barrel, yet the duller rifling of the Colt was not causing as much strain even though velocities where much higher.

We have a 14.5" Diemaco pencil barrel here at work, and its a submoa gun with 52gr Match, 55gr Match and several other match rounds.

All rifle barrels are not created equally is the best lesson to learn.
 
I shot a 3 rd. 2.5" group at 500m when zeroing the AR I use for service conditions competition. (68gr. Hornadys). Very pretty, saved the Fig.12, but statistically meaningless.
Even for comparing ammunition, 3 rd. groups are not definitive. A series of 3 rd. groups might be informative, but a series of 10 shot groups will be definitive. For service rifle, 10 shot strings are the norm, so it is important to know exactly how the rifle groups 10 shots at all ranges. The rifle and ammuntion have to be capable of holding the 5 ring with every shot - and the group needs to be somewhat smaller than the 5 ring, to allow for wind error.
 
chopper 1 said:
Agreed but the test was not for accuracy - it was to compare 69 grainers with 55's - the 69 grain 3 rd groups were much larger.
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You cannot use statistically incorrect samples as basis of comparison.

This is becuase the sample is invalid in the first place - the result is meaningless. Next, you don't have enough sample size to support your conclusoin..

There are two problems here - first, each group is considered a sample. Next, the number of shots that consistitutes a sample. Your sample is invalid, and there are not enough samples to support a conclusion.

Theoretically, it will need about 50 shot groups at least, to make a conclusion.
 
I shot another 800rds of 70gr today from 8 11.5" guns (testing stuff)

So 1600rds giving me a

1.565 MEDIAN1.535625 AVG


Now unfortunately I won't be able to test 55gr in this amount with these guns, but I should be able to get some data (200-400 rds) and probably about 1000rds of M855.

We go thru more than 50k rounds a week here in testing (5.56mm) and 10k or so of 7.62mm
 
Bettya

Bettya -
If I shoot several 50 rd 55 gr. group and several 50 rd 62. gr. group outta my shortie - (I have) the 62 will be larger !
My 3 rd groups were cheaper - but statistically meaningless -

"There's lies , damn lies , then there's statistics" - Mark Twain :)
 
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