[tenntyrant]

WHat would be a good bullet weight to have stocked up in case you ever need it for rifles with a 1:7 and a 1:9 twist 5.56 223 one round that will shoot good in both. I'm thinking 69 grain what's your thoughts?

[BenLuby]

You looking for a midrange grain that works well in both, or separate? I think I'd opt for one that works well in both calibers, because you're not talking a major variance in twist rate. The 1:7 is obviously faster, but somewhere in the 60 category would work well.

[Jpyle]

55gr or 62gr will work equally well and should be abundant in bulk at reasonable prices...at least for now.

[Quentin]

Originally Posted by Jpyle

55gr or 62gr will work equally well and should be abundant in bulk at reasonable prices...at least for now.

I agree, 55-62gr should be optimal for most 1:7 and 1:9 ARs. And reasonably priced.

[Duck4Glocks]

What about a 1:8 twist?

[Jpyle]

Originally Posted by Duck4Glocks

What about a 1:8 twist?

No difference. For all practical purposes, 1:7, 1:8 and 1:9 will all perform more or less the same with 55-62gr ammo. Unless you are shooting extreme distance with longer, i.e. heavier loads or heavy tracer rounds, there is nothing gained between a 1:7 and a 1:9. Lighter, varmint rounds in the 40gr or so range may need a 1:9 or 1:12 to prevent overspin.

[Shade]

Here is something that may help your decision out.

http://kwk.us/twist.html

[nickel1911]

Originally Posted by Shade

Here is something that may help your decision out.

http://kwk.us/twist.html

What a great link! Thanks for posting

[purehavoc]

Your going to have to shoot both 55 and 62 gr and see how they shoot out of your guns , both of mine will shoot 55 but one of them is not as accurate with it and both barrels are 1:7 both by the same manufacturer , they both shoot 62 about the same and much better than the 55 gr . just buy a couple boxes of each and try them out yourself .

[BenLuby]

Originally Posted by purehavoc

Your going to have to shoot both 55 and 62 gr and see how they shoot out of your guns , both of mine will shoot 55 but one of them is not as accurate with it and both barrels are 1:7 both by the same manufacturer , they both shoot 62 about the same and much better than the 55 gr . just buy a couple boxes of each and try them out yourself .

If both your barrels are chrome lined, that could have something to do with it, as chrome doesn't make a perfect bond, and thus, each barrel will be different. Thus, shooting a lighter 55 grain will give different results than shooting the heavier 62 grain bullet. Another thing would be what ranges do the differences become quite apparent?