bbl twist rates

[kgj1119]

Im purchasig a rifle shortly, and i have an unlimited supply of 55gr. rounds. What bbl twist should I get 1x7, or 1x9?

[Cold Zero]

The 1 in 9 twist rate is used for bullets 55-62 grs, or basically training ammo. The 1 in 7 twist will stabilize heavier bullets like the 75 gr. T.A.P. 77 gr. B.H..

I would go with the 1 in 7 since it will serve both purposes. Hope that helps.

[deadwood83]

Between the two options you listed, i'd say it depends.

If used as a hunting rifle, use the 1:9. If used as a match/service/home def/service rifle then go 1:7.

Or just build a rifle and use a barrel with a 1:8 twist to get the best of both worlds!:D

[C4IGrant]

Between those two options, I would go with 1/7 (as you can always go to heavier ammo if you want). With that said, I would look for a 1/8 twist barrel as it will shoot the 55gr a little more accurately.



C4

[RyanH]

I don't mean to hijack your thread but this is something that I'd like to get some more information on too.

I'm building an AR right now and I thought I'd pretty much made up my mind on a 16" barrel with a 1/9 twist.

It's going to be primarily for messing around at the range and home defense. The only time I could even conceive of shooting further than 100 yards is if I take it with me to Camp Perry next summer.

So what you guys are saying is that a 1/9 barrel isn't the best choice for that? I should probably go with a 1/8 or 1/7? After reading through this site (http://www.ammo-oracle.com/) and coming across this article (http://www.ammo-oracle.com/body.htm#twists), I really thought I'd made a good decision. :confused:

Thanks for any input and sorry again about butting in on your thread. BTW, how in the hell did you get access to an unlimited supply of ammunition?! That must be nice. :)

-Ryan

[TWR]

I guess it all depends on your use. If I had an unlimited supply of 55 grain bullets I'd choose the 1/9 twist but I'm just a hunter and the 55 grain does everything I need to do.

I do have 2 1/7 twist barrels as well so I can pick a bullet and twist for the intended job. But as Grant and Deadwood stated the 1/8 twist would probably handle most all bullet weights (lengths).

[Robb Jensen]

If you will never be shooting bullets heavier than 69gr go with 1x9. If you want the option of shooting basically anything from 45gr-77gr go with 1x7.

That said I only have 2 of my 8 ARs with 1x9, the rest are 1x7. 90% of the time I shoot 55gr.

[Logic]

I too agree with the 1-8 twist recommendation, as it will handle most everything without having to go either left or right, if you know what i mean. I started with 1-9 then moved to 1-7 and now have settled in with the 1-8.

[C4IGrant]

If your going to use the AR for HD, then I would REALLY look at 1/8 or 1/9 as the best defensive rounds made are the 75gr TAP and 77 MK (MK262).

Remember that 1/7 will shoot 55gr pretty well.


C4

[hercules]

How well does the Horn. TAP 75 shoot from a 1/9 verses the 60 gr TAP?

herk

[C4IGrant]

How well does the Horn. TAP 75 shoot from a 1/9 verses the 60 gr TAP?

herk

All the TAP line is excellent IMHO. You COULD shoot 75gr in a 1/9, but I don't think you would get any kind of accuracy out of it. It is also possible that it won't agree (fit) with your barrel. :D


C4

[TJUrban]

KGJ - The accuracy I get from a barrel depends as much on the length of the projectile as its weight, the ogive of the bullet, the quality of the barrel and the "jump" from the cartridge case mouth to the rifling.

While you could shoot 55g projectiles all day long out of a 1/12 twist barrel, you would be understabilizing 69 grain and longer/heavier bullets, which is bad. Similarly, 1 in 9 is too slow for the really long 80g bullets people shoot at 600 yards, I'm told.

On the other hand, you have to get pretty extreme to see a negative effect from "over stabilizing",as it were, with fast twists. An example of too fast a twist might be shooting 40 grain lightly jacketed varmint bullets with max velocity loads out of a 24" 1/7 twist barrel - in that case the light jacket could actually fragment in midair.

I use two 1/8 twist .223 ARs to compete in NRA service rifle class, and both will shoot 52 grain flat base Sierra Match Kings into very small groups off a bench. So there's a light bullet with a relatively fast twist - no problem. Both rifles have premium quality barrels - and I think that is a very important factor.

best regards to all

Tim

PS Hi Grant