Optimum barrel length and twist for 223?

[DXHI]

Post says it all looking at building a 5.56x45 / 223 rem and wanting the optimum battle length and twist for 55 gr or heavier bullet out to 300 yds for coyotes

 

[WildRose]

The 5.56 was specifically developed for 16-20" barrels and performs very well in them.

Again, just like with the .308 there is only a minimal gain in velocity with longer barrels with perhaps one exception which would be in using the heavy for caliber VLD's using slower burning powders than those developed for use in military rifles.

Honestly you could probably get better information on both calibers over as Sniper's Hide or Sniper Central for more detailed discussion as you will fine a whole lot more guys shooting both calibers there.

 

[Capt. D]

I just started a new build on a 223 AI. The rifle will be a dedicated predator rifle with a can hung off of the end. I went with a Benchmark barrel finished at 22" with a 1 in 8 twist for the heavier bullets.

Coyote hunting, you're typically shooting off of sticks so length is really not an issue but the shorter barrel will give you more manuverability. The 1 in 8 is fine for 55 grainers but I like the heavies hence the faster twist rate. Hides dont get very good in south Texas so I'm not really concerne about tearing up a hide. We hunt primarily for predator control (cattle and wildlife) and of course for the fun of it. A 223 to 400 yards with this set up should be a non issue.

 

[WildRose]

I just started a new build on a 223 AI. The rifle will be a dedicated predator rifle with a can hung off of the end. I went with a Benchmark barrel finished at 22" with a 1 in 8 twist for the heavier bullets.

Coyote hunting, you're typically shooting off of sticks so length is really not an issue but the shorter barrel will give you more manuverability. The 1 in 8 is fine for 55 grainers but I like the heavies hence the faster twist rate. Hides dont get very good in south Texas so I'm not really concerne about tearing up a hide. We hunt primarily for predator control (cattle and wildlife) and of course for the fun of it. A 223 to 400 yards with this set up should be a non issue.

You might want to reread and edit. You're recommending the same 1:8 twist for both the heavies and the 55's.

Berger recommends 1:12 twist rate for their heaviest .22cal bullets and 1:15 for their lightest .22's.

According to Nosler 1:12 is the standard for the caliber but suggests a faster twist for their 60gr.

I find another chart that isn't attributed to anyone in particular from another forum that suggests 1:7 for .22cal 90gr bullets.

The more I look the crazier it gets!

Did you mean to say you were going with a 1:7 for the heavies?

 

[WildRose]

You might want to reread and edit. You're recommending the same 1:8 twist for both the heavies and the 55's.

Berger recommends 1:12 twist rate for their heaviest .22cal bullets and 1:15 for their lightest .22's.

According to Nosler 1:12 is the standard for the caliber but suggests a faster twist for their 60gr.

I find another chart that isn't attributed to anyone in particular from another forum that suggests 1:7 for .22cal 90gr bullets.

The more I look the crazier it gets!

Did you mean to say you were going with a 1:7 for the heavies?

I meant to ask, what increase in velocity are you getting with the .223AI as compared to the standard .223?

I shoot the .220 swift and have for several decades and love it, I would think that the .223AI compares pretty favorably with the Swift and 22-250.

 

[Capt. D]

Wildrose
As for the recommendation of the 1 in 8 twist rate, from a 22-250 I have shot bullets from 50gr up to 80 gr in a 1 in 8 twist all half minute or better but settled on the 69 gr SMK BTHP for my primary bullet choice. The Nosler 77 gr BTHP is my secondary choice. Both shoot one ragged hole at 100 yds and I have had the SMK's beyond 400 yds maintaining less than half minute accuracy. I have not stepped the Noslers out yet. Granted its not a 223 but a 50 to 80 grain bullet range in a 1 in 8 shouldn't be a problem. I wasn't trying to give an optimum twist for a given bullet weight. Just my own experience. I'm sure at some point a bullet can be spun to fast but I don't know what that threshold is. And no I have not tried the 90's because I don't believe an 8 twist will stabilize it. (A buddy of mine shoots a 1 in 8, 223 and drives tacs throwing 55 grain Hornadys down range)

As far as velocity goes with the 223AI, I don't know I just ordered the barrel a couple of weeks ago from Benchmark. I have an old savage 110 that I am going to do the barrel swap myself and put it into a precision stockworks stock. I would think that It would compare as well, probably wouldn't be doing it except for the fact that I had the action anyway. And its something I want to try doing myself.

 

[DXHI]

Yea I was going to do a 1:8 I saw several companies offering match barrels in this configuration

 

[benchracer]

Your intended purpose (coyotes out to 300 yards) leaves your options pretty wide open. An 8 twist will work well with bullets ranging from the 55 grain you mentioned to the 75 AMAX. You don't need to go heavy to reach out to 300 yards, but I would bet that you will eventually want to try the heavies anyway, so you may as well go with the fast twist. It won't hurt you on the light end and will give you more overall flexibility.

IMO, 24" of barrel length will give you just about everything you are going to get from a .223/5.56mm. You can go longer, but you will quickly enter the land of diminishing returns. Anything between 20" and 24" will work well. I prefer the 5.56mm NATO chamber to the .223 chamber for its greater versatility, being able to digest a wider variety of ammo and allowing for heavy bullets to be seated longer.

 

[Kansaswoodguy]

I have 1-14,1-12, 1-9, 1-8, and 1-7 twist 223's they shoot 55's just fine.I mostly use 1-8 twist it will stabilize 75gr bullets no problem which are my favorite bullets in 223. With such short a range requirement as you stated I think I'd go lighter as your already suggesting. The heavies buck the wind better but have more drop I think with unknown distances of only 300 yards light and fast is going to be better. 5.56 NATO was designed for a 20" barrel and it is my favorite barrel length and I like the way it balances when just in front of the mag well in AR's for hand carrying it. The shorter barrels balance under the mag well unless your using a bull 16" barrel which again puts the balance point just infront of the mag well again. Now if your using a bolt gun the barrel length is less important to get the guns balance right. Your going to be able to run any twist and really any barrel length if your only shooting out to 300 yards is what I'm saying.

 

[DXHI]

Thanks for all the replies

 

[Tare]

You might want to reread and edit. You're recommending the same 1:8 twist for both the heavies and the 55's.

Berger recommends 1:12 twist rate for their heaviest .22cal bullets and 1:15 for their lightest .22's.

According to Nosler 1:12 is the standard for the caliber but suggests a faster twist for their 60gr.

I find another chart that isn't attributed to anyone in particular from another forum that suggests 1:7 for .22cal 90gr bullets.

The more I look the crazier it gets!

Did you mean to say you were going with a 1:7 for the heavies?

I built my AR for 90gr SMKs so I got a 1:7 18". I would have went with a 1:6.5 to shoot 90gr VLDs but that would've been more than I wanted to spend.
I can still shoot light bullets through it, over spinning won't hurt anything unless they are unbalanced or have thin jackets .

I believe the twist rate recommendations are generally minimums required for stability.

 

[blacknzr1]

My standard tikka in .223 1:8 shoots 50gr up to 80gr with no problems. I will say it didn't seem to like 55gr though.

 

[WildRose]

I built my AR for 90gr SMKs so I got a 1:7 18". I would have went with a 1:6.5 to shoot 90gr VLDs but that would've been more than I wanted to spend.
I can still shoot light bullets through it, over spinning won't hurt anything unless they are unbalanced or have thin jackets .

I believe the twist rate recommendations are generally minimums required for stability.

I generally would agree with that although at extreme velocities I've seen light jacketed bullets come apart completely in 17 Rem's, .220 Swift, and .204 Ruger.

Other than that I have a hard time buying into the idea that over spin is a problem at all. I've just never seen any convincing evidence.

 

[Garycrow]

My 1-8 twist .223 shoots 40 gr. nosler ballistic tips really well. A fast twist will still shoot the lightweights, it's pretty much a myth that they'll only shoot heavier bullets well.