55gr .223

[sgreen3]

Ive did some research and cant find anything really rock solid, but is a 1:8 barrel good to stabalize a 55gr bullet in an AR? The AR is going to be used for target shooting. So any help would be appreciated.

 

[sloughfoot]

A 1:8 barrel will stabilize all 223 bullets up to, and including, 80 grain.

 

[redwingshooter]

A 1:8 barrel will stabilize all 223 bullets up to, and including, 80 grain.

What he said, you are G2G!

 

[sgreen3]

A 1:8 barrel will stabilize all 223 bullets up to, and including, 80 grain.

Thanks Slogh, thats what i was thinking but wanted to double check

 

[msd]

Your rate of twist slower will stabilze heavier bullets.

Heres what I've found to be true in all my AR's.
1-7" twist is ideal for 55gr bullets......period.
1-9"twist is ideal for 62gr bullets and up....period
My Stags are 1-7 My Colts are 1-9
My stags at 25yrds with 62gr FMJ, we're talking 1" groups @ 25 yrds. Dead center.
At 200 yrds, 3" groups
With 55gr bullets, 2" high @ 25yrds, @ 200yrds 1/4" grps
My Colts @ 25 yrds with 62 gr 2" high sub moa
@ 200yrds, dead on 1/8" grps

 

[Leo]

My experience, which like sloughfoot, is 10's of thousands of rounds in registered competition is: 1 in 7 will stablize from 52 grain matchkings to 77 grain matchkings and Berger VLD. I never shot 80's becaquse I was cleaning the 600 yard targets with the 77 grain bullets. 1 in 7.7 twist (kreiger barrels) will also stablize all of the above as will a 1 in 8. A quality 1 in 9 barrel will stablize from 52 grain to 69 grain match bullets. When I define stablize, I mean sub one inch groups at 100 yards and dependable sub MOA at 200, 300, and with the 75/77 grain bullets, 600 yards. I have a stock bushmaster DCM that cut 1-1/2 inch groups at 100 with cheap HUNTING bullets, iron sighted and shot prone, no bipod. (I posted pictures a few weeks ago, Dogtown bullets) If the barrel is of those twists it it will shoot those bullets well. The quality of the barrel and the quality of the bullet are the big factors. You can put a junky bullet through the finest benchrest barrel HART ever made, and it will shoot poorly. You can put a Sierra MatchKing through a cheap combat barrel, and it will shoot poorly. But put a quality bullet through a quality barrel, and you do your part, the target becomes a thing of beauty.

I cannot really comment on third world or combat bullets, I never plink with a centerfire rifle, so I don't shoot plinker grade ammo.

 

[sloughfoot]

msd, you obviously have two rifle/bullet combinations that give results that please you. Congratulations.

But the basic logic is flawed. Using your line of reasoning the 75 AMAX and the 80 SierraNoslerHornady......etc will be stabilized by the 1:9 barrel.

They just will not. They will keyhole through a 25 yard target. They require a 1:8 or 1:7 twist barrel.

 

[Chefcook]

After quite a bit of extensive shooting I have found that my rifles have certain ammo that they just like better than others. My Oly 1:9 twist likes Lake City M855 Gr tip 62gn. bullets the best and my LMT barreled AR 1:7 twist loves Privi Partizan 75gn. Both stabilize 55gn bullets ok but accuracy is not as good. I still shoot .55gn for general plinking but if accuracy really counts I stick to the other two. Generally 1:9 twist was developed mainly for civilian use and should stabilize anything from 55-69gn, while 1:7 twist was generally for military rifles so the heavier armor piercing and tracer bullets would stabilize. Nowadays 1:7 is pretty common as well as 1:9. Many varmint rifles like bolt guns often have a 1:12 twist to stabilize much lighter bullets as did the original M-16. Always remember every rifle is different and has a certain load it will shoot better than others. Shoot a lot and try out different brands and bullet weights. If you like to reload you can really have a lot of fun working up a gun specific load..

 

[lovemywoods]

Your rate of twist slower will stabilze heavier bullets.

Heres what I've found to be true in all my AR's.
1-7" twist is ideal for 55gr bullets......period.
1-9"twist is ideal for 62gr bullets and up....period
My Stags are 1-7 My Colts are 1-9
My stags at 25yrds with 62gr FMJ, we're talking 1" groups @ 25 yrds. Dead center.
At 200 yrds, 3" groups
With 55gr bullets, 2" high @ 25yrds, @ 200yrds 1/4" grps
My Colts @ 25 yrds with 62 gr 2" high sub moa
@ 200yrds, dead on 1/8" grps

Let's take this a section at a time. (Your original comments in red.)

1.
Your rate of twist slower will stabilze heavier bullets.

Everything I've read says the opposite is true. (Let's check definitions: "1:7" means one complete revolution in 7" of the barrel.) A 1:7 twist is a 'faster twist' than a 1:9. The 1:7 barrels are better for the heavier bullets. 1:9 is better for the lighter rounds.

2.
Heres what I've found to be true in all my AR's.
1-7" twist is ideal for 55gr bullets......period.
1-9"twist is ideal for 62gr bullets and up....period

A 1:9 barrel will stabilize bullets in the 45 to 62 grain range, and 1:7 will stabilize bullets in the 55 to 77 grain range. This is a general guide. There are many other variables that can affect bullet performance. Your experience seems to contradict that guideline.

3.
My Stags are 1-7 My Colts are 1-9

Although the majority of Colts are 1:7, they do make some with 1:9 barrels. No issue here.

4.
My stags at 25yrds with 62gr FMJ, we're talking 1" groups @ 25 yrds. Dead center.
At 200 yrds, 3" groups
With 55gr bullets, 2" high @ 25yrds, @ 200yrds 1/4" grps

Let's talk MOA here to make it easy to compare performance as the distance changes. You didn't mention the number of rounds you were shooting in each group. I'll assume it's at least five.

1" groups, 25 yards, 62 gr bullet = 4 MOA

3" groups, 200 yards, 62 gr bullet = 1.5 MOA

1/4" groups, 200 yards, 55 gr bullet = .125 MOA
This must be a typo or it's BS. A standard AR platform rifle won't produce .125 MOA accuracy. It's also not reasonable for there to be a substantial improvement in MOA results with increasing distance.

5.
My Colts @ 25 yrds with 62 gr 2" high sub moa
@ 200yrds, dead on 1/8" grps

25 yards, 62 gr bullet = <1 MOA
1/8" groups, 200 yards, 62 gr bullet = 0.06 MOA!
Something is not right here. What you are reporting is not reasonable or doable with the equipment you list.

I suggest you re-think your assertions here.

 

[sgreen3]

The upper I ordered is a 1:8 twist. I just wanted to see what I should shoot if Im looking for the best accuracy I can get. What Ill probably end up doing is to shoot some of the 55gr stuff out to 100yrds to get it sighted in. An when I start to move out further ill step up to some of the 69gr match stuff and see what the gun likes the best.

 

[U.S. Patriot]

I have found that my Bushy 1:9 shoots AE223 really well. I have not fired any 62 grain ammo yet. I will be loading some to test though.