AR 15 Barrel 1:9 Twist?

[xring01]

I am very new to the AR Seen... Been doing the Varmint Match, 1000yd, 1500yd, even 2000yd stuff for years...

Anyway, I am in the process of building a low budget AR15 for my son...

My question, how big of a bullet can a 1:9 twist 223 barrel stabilize...

 

[MWM-5150]

Re: AR 15 Barrel 1:9 Twist?

55's ideally

I've also had some good luck with hand loaded 62s and even 75s depending on the distances I'm shooting.

From my barrel, my best performance has been the 55s.

 

[Graham]

Re: AR 15 Barrel 1:9 Twist?

It's 'Scene'.
There is no 2000yd 'stuff', certainly not 'for years'.
And by 'how big', do you mean how long or how heavy?

The answer is: It depends. It depends on the bearing surface of the bullet, on the barrel and on the temperature.

Probably 70's, maybe some 75's. Not 80 VLDs.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MWM_5150</div><div class="ubbcode-body">and even 75s depending on the distances I'm shooting.</div></div>Stability is not a function of distance. Either a bullet is stable, or it isn't.

 

[Houston Armory]

Re: AR 15 Barrel 1:9 Twist?

if you are looking at statistics such as velocity, bullet drop, bullet grain, you are going to get your best out of something like a 65gr sierra game king, that is probably going to be the biggest size bullet that a 1:9 twist ratio barrel will be able to maximize the stability of out towards the distance the platform was designed to achieve.

 

[355sigfan]

Re: AR 15 Barrel 1:9 Twist?

It depends on the length of the barrel to a point bu 69 grains is easy for a 1/9 but some longer 1/9's will work wtih 75's and 77's some won't.
Pat

 

[Temp9]

Re: AR 15 Barrel 1:9 Twist?

A true 1:9 should stabilize a 75gr Hornady BTHP at 2700fps with no problem at sea level and 85F. You may have problems at lower temperatures, though.

69gr SMK's will work fine at whatever temperature.

 

[GFWTF]

Re: AR 15 Barrel 1:9 Twist?

I like the 69gr SMK, and the 62gr green tip nope nex that they the blue fmj, no issues and mine is being fired out of a 7.5" SBR, I refer to as the toy.

 

[Cegorach]

Re: AR 15 Barrel 1:9 Twist?

A 1/9 will stabilize the 70 vld, which is going to be about the best performing AR magazine length bullet out there. It has a BC equivalent to the 75/77 bthp/smk and can be pushed faster.

 

[Downzero]

Re: AR 15 Barrel 1:9 Twist?

Do yourself a favor and just get a 1 in 8 barrel.

 

[Graham]

Re: AR 15 Barrel 1:9 Twist?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Downzero</div><div class="ubbcode-body">Do yourself a favor and just get a 1 in 8 barrel. </div></div>Yes, if it's a true 8-twist.

The 9-twist should shoot 70gr Berger LTBs very well at mag length with the right powder. That should get you to 800 yards.

 

[battlestick]

Re: AR 15 Barrel 1:9 Twist?

Check your rifling yourself to be sure. I have a 16" RRA 1:9 barrel, it is dang near 1:8.5.

I run 75gr Hornady HPBT handloads @ 2675 to 500 easy, and on low wind days she will lob them out there to 750.