AR barrel twist

[gregkl]

1:7 twist like them heavy bullets. But yes, load development for your gun if you reload. 1:9 shoots 55gr and less.

It really boils down to the distance you want to shoot. Heavier bullets will hold up better the farther out you go.

So if I want a rifle that will shoot some distance, say 400+ yards and I use a 1:7 barrel, will it still be okay for closer(<100 yards) stuff with a lighter weight bullet?

 

[avboiler11]

A 1:9 will shoot 75/77 HPBT bullets just fine.

Sometimes I quote myself.

That's from 1:9 barrel; I hit 8" steel at 650yd with ease (unless I dorked the wind call).

 

[sgreen3]

Sometimes I quote myself.

That's from 1:9 barrel; I hit 8" steel at 650yd with ease (unless I dorked the wind call).

 

[avboiler11]

Here's another example of how a 1:9 223 won't shoot 75/77s:

That's 100 yards, 5 shots, 75gr Hornady HPBT and 24.0gr Varget.

 

[Cerberus]

Congrats AV, exactly 1 of the 4 1:9 ARs I tried gave decent groups with 77gr SMK reloads, and it was a 16" barrel. All 7 ARs, 3 1:7 and 4 1:9 examples ran 45 and 55 gr fodder well, and all the Military twist rifles ran the 77 grainers

 

[__Doc_]

Easiest way to remember this

High grain --> low twist
Low grain --> high twist

 

[Mgderf]

O.K. say I have a 1:8 twist in a 24" barrel and I want to shoot out to 500 yards/meters.

What's my optimum weight, theoretically?

 

[avboiler11]

O.K. say I have a 1:8 twist in a 24" barrel and I want to shoot out to 500 yards/meters.

What's my optimum weight, theoretically?

68-77gr, whichever bullet type and weight shoots best.

I shot 77gr Nosler CCs @ 2660fps out to 900yd with a 18" 1:8 AR a couple weekends ago. I scored 1 hit out of 10 on a 12" round plate, with the other 9 rounds just to the left or right of the plate.

Given it was my first trip shooting beyond 650yd and I'm still learning how to properly drive a gas gun, I was pretty happy.

 

[Mgderf]

68-77gr, whichever bullet type and weight shoots best.

I shot 77gr Nosler CCs @ 2660fps out to 900yd with a 18" 1:8 AR a couple weekends ago. I scored 1 hit out of 10 on a 12" round plate, with the other 9 rounds just to the left or right of the plate.

Given it was my first trip shooting beyond 650yd and I'm still learning how to properly drive a gas gun, I was pretty happy.

I'd say that with some practice, and a little "Kentucky windage", that sounds like loads of fun.

 

[melensdad]

O.K. say I have a 1:8 twist in a 24" barrel and I want to shoot out to 500 yards/meters.

What's my optimum weight, theoretically?

Don't know but 50 grain Federals are the most accurate out of this 1:8 barrel.

 

[OldGoat]

Wow, haven't checked my post for a few days, thank you for all the great advice. In the beginning I was ask three questions
(1)Better for what purpose?
(2)How do you intend to use the rifle?
(3)What loads do you want to shoot?
1 and 2 I'm looking to use as a multi purpose tool, remove a ground hog or two, punch some paper just to make sure the sights and my old eyes still work and a stand off weapon if Hannibal ever does come to the gate.
I have a couple rounds of Mil surplus laying around, not sure I think it 55gr but now you guys got me going so I will investigate that more closely. I carried a M-4 in Afghanistan, some one mentioned most mil models was 1:7 it always worked well for me. Looks like I have a lot more research to do.Thank you all again for the great advice.

 

[Ketchup]

So if I want a rifle that will shoot some distance, say 400+ yards and I use a 1:7 barrel, will it still be okay for closer(<100 yards) stuff with a lighter weight bullet?

Yes, it will still be fine with the lighter grain bullets at 100yds or less. Hornady 55gr SP and FMJ both shoot sub moa in my 1:7 16" AR.

For 400+ yards you'll want a 18" bbl, just saying.

 

[gregkl]

Yes, it will still be fine with the lighter grain bullets at 100yds or less. Hornady 55gr SP and FMJ both shoot sub moa in my 1:7 16" AR.

For 400+ yards you'll want a 18" bbl, just saying.

The barrel I am looking at is a White Oak 18" SS 1:7 twist. I'm thinking of using that with a mid-length gas system for one build.

 

[avboiler11]

The barrel I am looking at is a White Oak 18" SS 1:7 twist. I'm thinking of using that with a mid-length gas system for one build.

WOA makes very good barrels...that should work nicely.

 

[Leo]

greg, that barrel will do the job.

 

[gregkl]

greg, that barrel will do the job.

Thanks Leo.