Best Barrel Twist/Length Combination for light .223 bullets

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[ARCHIVED THREAD] - Best Barrel Twist/Length Combination for light .223 bullets

Posted: 9/11/2014 11:23:54 PM EDT

Getting ready to buy a barrel for my 5.56 build. I like coyote hunting with a 50-55 grain bullet, no heavier or lighter. Keep hearing that a 1-9 twist will be best but need to go with 20" barrel. Was planning on a 16"-18" but now not sure what to do. Want it to be a tack driver with the 50-55 grain and that takes priority over trying to keep it short. Need some educated suggestions.

Posted: 9/11/2014 11:27:56 PM EDT

[#1]

1:9

Less barrel wear
Less pressure
Less spin drift
No risk of bullet coming apart due to high RPM of a 1-7 (It's rare)

I go for 1:8 to take every thing.

I read somewhere that M16's used to be made with 1:12 barrels where only 55gn was used.

But stick with 1:9.

Posted: 9/11/2014 11:36:48 PM EDT

[#2]

Quote History

Quoted:
1:9

Less barrel wear
Less pressure
Less spin drift
No risk of bullet coming apart due to high RPM of a 1-7 (It's rare)

I go for 1:8 to take every thing.

I read somewhere that M16's used to be made with 1:12 barrels where only 55gn was used.

But stick with 1:9.

View Quote

I'd go with 1/12", keep in mind the ORIGINAL twist was 1/14"

Being that I NEVER fire heavier than 55 gr. I have several 1/12" barrels. They are DAMN accurate.

Posted: 9/12/2014 12:30:44 AM EDT

[#3]

Correct. I would just go with a 1-9. That can take 62gn ammo also.

It's hard to find 1:12's.

You can get a 1:9 with some good perks like melonited, 54, different profiles, etc.

Posted: 9/12/2014 4:23:34 PM EDT

[#4]

you say you want it to be a tack driver with 50-55 grain bullets? if that is truely
what you want than you want a 1:12 twist. anything else is a compromise, with
the benefit of being able to shoot heavier bullets.

they are not hard to find, call the major barrel manufactures in the us. (ie green mountain,
kreiger, douglas, lilja, ect someone out there will build you a barrel) green mountain
has 1:12, A1, 20" in stock right now.

what you will not find is a wide selection of profiles, or lengths. most will be bull barrel
or lightweight A1 profile, generally 20"-24".

Posted: 9/12/2014 8:43:40 PM EDT

[#5]

Quoted:
Getting ready to buy a barrel for my 5.56 build. I like coyote hunting with a 50-55 grain bullet, no heavier or lighter. Keep hearing that a 1-9 twist will be best but need to go with 20" barrel. Was planning on a 16"-18" but now not sure what to do. Want it to be a tack driver with the 50-55 grain and that takes priority over trying to keep it short. Need some educated suggestions.

View Quote

http://www.gmriflebarrel.com/m16-a1-5-56mm-20-1-12-twist-20-barrel/

Posted: 9/12/2014 8:47:54 PM EDT

[#6]

Quote History

Quoted:
http://www.gmriflebarrel.com/m16-a1-5-56mm-20-1-12-twist-20-barrel/

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Getting ready to buy a barrel for my 5.56 build. I like coyote hunting with a 50-55 grain bullet, no heavier or lighter. Keep hearing that a 1-9 twist will be best but need to go with 20" barrel. Was planning on a 16"-18" but now not sure what to do. Want it to be a tack driver with the 50-55 grain and that takes priority over trying to keep it short. Need some educated suggestions.

http://www.gmriflebarrel.com/m16-a1-5-56mm-20-1-12-twist-20-barrel/

^^ This ^^

Posted: 9/12/2014 10:42:06 PM EDT

[#7]

Depending on air density and velocity 1:14 to 1:12.
AFAIK the military went to 1:12 to stabilize M193 55gr bullets in artic conditions.
1:12 is a safe bet.

Posted: 9/12/2014 11:34:26 PM EDT

[#8]

Quote History

Quoted:
Depending on air density and velocity 1:14 to 1:12.
AFAIK the military went to 1:12 to stabilize M193 55gr bullets in artic conditions.

View Quote

You are CORRECT!!!

Posted: 9/13/2014 4:42:28 AM EDT

[#9]

I've had 7.7 twist barrels that shot 55s just fine. If you want it to be a tack driver I'd say more important than the twist rate is a quality custom barrel.

Krieger has many AR barrel blanks in stock and they will chamber and fit a barrel extension if you want. My preference is to have my gunsmith chamber a barrel.

B

Posted: 9/15/2014 10:37:01 PM EDT

[#10]

GM does have the A1 style in stock, will I have any fit issues with upper or accessories? Not stopping my search there, but it is a good start. probably be simpler to just make 55 grain my bullet choice and go with the 1:9, but really like lighter bullets because of less damage to pelts.

Posted: 9/15/2014 10:45:09 PM EDT

[#11]

Quote History

Quoted:
1:9

Less barrel wear
Less pressure
Less spin drift
No risk of bullet coming apart due to high RPM of a 1-7 (It's rare)

I go for 1:8 to take every thing.

I read somewhere that M16's used to be made with 1:12 barrels where only 55gn was used.

But stick with 1:9.

View Quote

Yes, everything was 1/12 for a long time. My HK93 is 1/12, My old SP1 & CAR, etc. I actually don't really care about 1/7 that much except on a couple of rifles. I shoot 55 grain 90% of the time anyhow.

Posted: 9/18/2014 8:32:20 AM EDT

[#12]

Quoted:
Getting ready to buy a barrel for my 5.56 build. I like coyote hunting with a 50-55 grain bullet, no heavier or lighter. Keep hearing that a 1-9 twist will be best but need to go with 20" barrel. Was planning on a 16"-18" but now not sure what to do. Want it to be a tack driver with the 50-55 grain and that takes priority over trying to keep it short. Need some educated suggestions.

View Quote

Bob: FWIW, I have a 20" Green Mountain barrel with a 1in8 twist. I've tried a variety of bullet weights/lengths from 52 to 69 grains. My best results and pet load is with Sierra 53 grain Matchkings and Berger 52 grain target bullets, both are flat based. With 25 grains of Benchmark at about 3050 fps, on a good day I can put 10 rounds into less than an inch at 100 yards. This barrel can do the same with quality 62 and 69 grain, but not as easily. As for 1in12" twists the military used, bear in mind they wanted FMJ bullets to be barely stabilized for maximum wound potential, while civilian shooters want maximum accuracy and rely on bullet design for terminal performance. - CW

Posted: 9/18/2014 9:35:55 AM EDT

[#13]

A barely stabilized bullet is more accurate than an over stabilized bullet.
Of course the quality of the bullet is a determining factor in how big the difference is.
There is a formula for figuring the change in group size at various bullet RPMs.

Posted: 9/18/2014 11:27:10 AM EDT

[#14]

Twist rate relates to bullet length, not weight. As we run into new lead-free or all-copper hunting bullet designs, a bullet can be under 60 grains, yet too long to stabilize in a 1-12 barrel. I'd at least get a 1-9 twist.

Posted: 9/18/2014 12:05:01 PM EDT

[#15]

1/9 is a safe bet

I've never had problems running all types of 55gr bullets through my 1/7 barrel.

I haven't ran 45gr through my 1/7, but I did when I used to have a 1/9 and they shot just fine.

[ARCHIVED THREAD] - Best Barrel Twist/Length Combination for light .223 bullets

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