AR Upper with 1x7" Twist?

[Straight Shooter]

I've found a good deal on an upper with a 1x7" twist... 

"M4 16" 1x7 4150 Chrome Moly Vanadium Steel, 5.56 chambered, air gauged, Bull Dog barrel with M4 profile."

I have several .223's with 1x9" twists and a Howa Axiom with a 1x12" twist... they are real tack-drivers with 40-52 grain bullets.  I know that I can get up into the 70 grain-range with the 1x7" twist but, will it still do well with the 40-52 grain bullets?  In other words, is the any disadvantage (with stablization) with the faster twist?

Thanks,

SS

[FC]

You will have better stabilization with heavier projectiles in the 69-75gr range but should still shoot 62gr pretty well.

[Straight Shooter]

You will have better stabilization with heavier projectiles in the 69-75gr range but should still shoot 62gr pretty well.

How about the lighter (40-55 gr) bullets?

Thanks.

[FC]

How about the lighter (40-55 gr) bullets?

Thanks.

They will work but they won't be as accurate, if you want to shoot the lighter bullets I would stick with a slower twist.

[Straight Shooter]

How about the lighter (40-55 gr) bullets?

Thanks.

They will work but they won't be as accurate, if you want to shoot the lighter bullets I would stick with a slower twist.

Gotcha... thanks FC.

[demontang]

Unless your pushing the 40gr really fast i doubt you'll never see a loss in group size.  my 1in9 shoots the 40-60gr all well under Moa. I haven't tried anything heavier out of it yet

[FC]

Unless your pushing the 40gr really fast i doubt you'll never see a loss in group size.  my 1in9 shoots the 40-60gr all well under Moa. I haven't tried anything heavier out of it yet

That's a good point actually and one I didn't consider but if using factory bullets heavier bullets will still work better.

demontang how far are you loading down with the lighter bullets? If so what advantage do you see or seek from it or is it just a case of shooting what you have a ton of?

[demontang]

Well the 40gr I reload have been max loads and some are middle of the road loads. I've shot the factory hornady 40gr vmax which are listed at 3800. I think the bullets of today you would have a hard time with trying to spin them to fast out of a 223.

[Straight Shooter]

Well the 40gr I reload have been max loads and some are middle of the road loads. I've shot the factory hornady 40gr vmax which are listed at 3800. I think the bullets of today you would have a hard time with trying to spin them to fast out of a 223.

The 40 gr loads that I'm shoot are listed at 3650 fps.  So, there shouldn't be a problem with the 1x7" twist?   

[FC]

Only one way to find out

I'll have to try some of the Hornady.

[Blacklab]

I have a 20 in w/ a 1/7 twist. Handloads with 50 grain Nos bt work very well for me. Book says I'm pushing about 3200.

[Schwag173]

The Greenhill Formula (google it) will tell you 1:7 is better for the heavier (longer) bullets.  But depending upon how liberal your requirement is for accuracy, plain ole' 55-grainers may work just fine.  Every rifle has it's own tastes.  Handloading will also help because you can tune the ammo somewhat.  My 16" 1:8 barrel gives ho-hum accuracy with 55gr factory ammo, but when I feed it 77-gr handloads: