223AI...best twist?

[BoilerUP]

You've talked me into it...

I've pretty much decided my next Savage barrel will be a Criterion 22" 223AI in light varmint contour...only thing I'm not certain about is the barrel twist.

Intended purpose is paper and steel out to 650yd @ 500' ASL elevation, and I want to shoot the 80gr A-Max since it drifts a bit less than the 75gr A-Max even going 100fps slower. I think I can get 80s to around 2900-2950fps with a 22" tube.

I know 8 twist will stabilize the 75gr A-Max...will it suffice for the 80gr A-Max or should I just go with a 7 twist?

 

[el gordo2]

Re: 223AI...best twist?

I have a 24" 1:8 Rock and it handles the 75gr and 80gr Amax's equally well. If I was going to run 90 smk's or bergers then a 1:7 would be needed.

Amax's rock in the little AI.

 

[Niles Coyote]

Re: 223AI...best twist?

I went with a 7.5 twist Rock Creek as I was not sure an 8t would work 100% in the cold temps here in michigan with the 80 a-max. Just waiting for the barrel to arrive. My standard 223 7t shoots them fine FWIW.

 

[KYS]

Re: 223AI...best twist?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: el gordo2</div><div class="ubbcode-body">I have a 24" 1:8 Rock and it handles the 75gr and 80gr Amax's equally well. If I was going to run 90 smk's or bergers then a 1:7 would be needed.

Amax's rock in the little AI. </div></div>

Depending on speeds.... those 90gr Bergers are tricky to keep them in one piece according to Bartlein Barrels. I guess its all speed dependent.

 

[BoilerUP]

Re: 223AI...best twist?

This is probably waaaay overthinking it, but at 500' ASL/standard atmosphere with my current 223 (26" 9 twist) I get the following stability factors from the "Shooter" app:

75gr HPBT @ 2860: 1.41
75gr A-Max @ 2915: 1.01 (shoots great @ 100yd, stretching it out next trip)

An 8 twist at 223AI speeds shows the following:
75gr A-Max @ 3000: 1.29
80gr A-Max @ 2900: 1.19

And with a 7 twist:
75gr A-Max @ 3000: 1.69
80gr A-Max @ 2900: 1.55
90gr Berger @ 2800: 1.35

 

[STR]

Re: 223AI...best twist?

I wanted a 1 in 8 which I believe is ideal, but settled for a 1 in 8.5 because I wanted it now. It shoots the AMAX 80s great up close. Don't know how it will do at longer distances, but I expect good results. My barrel is a Bartlein, which a friend of mine sold me. I have loaded with Varget, and RL15 starting at 24 grains, and topping out at 25.1 on both. The best results accuracy wise were at 24.8 grains in both powders. The chrono I have sucks, so I can't offer reliable MV now. Hope this helps.

 

[jwp6114]

Re: 223AI...best twist?

my gun smith wasn't sure what bullets would stabilize in my 243's factory 9 1/8 twistm barrel before we AI's it, we thought maybe 80-90 grain, but it shoots 105 a-max like a champ.

the extra velocity = more rpm no matter what the caliber or twist rate of the barrel.

 

[ggmanning]

Re: 223AI...best twist?

I am running 75 and 80 amax's at 2800+/- in a 1:8

 

[kraigWY]

Re: 223AI...best twist?

If in doubt, go 1:7, we know it will shoot 90s.

The 1:7 will shoot light bullets, but slower twist wont shoot heavy bullets.

You can't go by what a gun/twist will do at close range. My Colt 1:12 SPI shoots 64 grn Speer Gold Dots great at 100 yards. It starts to loose it at 200 and completley useless at 300.

Then again my 1:7 White Oak upper shoots excellent groups w/52 gr SMKs.

I'm been playing with my Mann Accuracy Device (Rem action, 1:7 Kart Barrel). The army used 52 grn SMKs to test the device.

So you can pretty much shoot any =/> 50 grns with a 1:7, not so with the slower twist.

 

[SingleShot85]

Re: 223AI...best twist?

I have a 1:7.75 on a 22-250 and it spins 80's down to 69's just fine

 

[Niles Coyote]

Re: 223AI...best twist?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BoilerUP</div><div class="ubbcode-body">This is probably waaaay overthinking it, but at 500' ASL/standard atmosphere with my current 223 (26" 9 twist) I get the following stability factors from the "Shooter" app:

75gr HPBT @ 2860: 1.41
75gr A-Max @ 2915: 1.01 (shoots great @ 100yd, stretching it out next trip)

An 8 twist at 223AI speeds shows the following:
75gr A-Max @ 3000: 1.29
80gr A-Max @ 2900: 1.19

And with a 7 twist:
75gr A-Max @ 3000: 1.69
80gr A-Max @ 2900: 1.55
90gr Berger @ 2800: 1.35 </div></div>

I have had good luck with anything above a 1.1 but wanted to be closer to 1.4 for this project.

 

[SuperSeal110]

Re: 223AI...best twist?

1/8.

 

[7mmRM]

Re: 223AI...best twist?

1-8

 

[KYS]

Re: 223AI...best twist?

I wonder what a gain twist barrel could offer the 223AI in performance?

 

[BoilerUP]

Re: 223AI...best twist?

What kind of dies are folks using with their 223AIs?

I've already got a Lee Collet die for 223 which I've read will work...is there a need for a FL or body sizing die with the Ackley?

 

[223ai]

Re: 223AI...best twist?

Redding for everything.

 

[BoilerUP]

Re: 223AI...best twist?

Barrel ordered today...Criterion 22" 1:7 light varmint 223AI prefit for Savage small shank action...wait should be about 12 weeks.

Was told freebore in Criterion's 223AI prefits is 0.061 (standard 223 is 0.025, Wylde 0.078)...this okay for 80gr Amax? Is it too short for 90gr Bergers?

 

[BillCh]

Re: 223AI...best twist?

Did you plan on loading from the magazine? What are you expecting the OAL of a loaded round to be?
My 223 AI freebore is .077. That puts a 80.5 gr. Berger touching the lands at 2.480 OAL and a 75 gr. A-Max at 2.520.

B

 

[BoilerUP]

Re: 223AI...best twist?

Bill I think you responded to my question about this on AccurateShooter. Thank you for your OAL measurements, and to answer your question I will be using AICS 10rd polymer 223 magazines.

Your freebore/COAL measurements confirm for me that the 75gr A-Max should load to 2.504" OAL in my 0.061" chamber. That should work quite nicely for my needs.

Still trying to figure out of the 90gr VLD is worth trying; based on what I've been able to gather it should it the lands at 2.496" OAL.