I am in the market for a new 16" mid length gas system upper.
I am truly LOST on which twist rate to get.
1x9 was reputed to be the best "All around" twist rate back in the '90's.
But I hear a chrome lined 1x9 won't stabilize a 77gr projectile?
1x7 will stabilize the 77gr but the 55gr is useless in it.
So  wouldn't it be logical that the 1x8 barrel would do everything between and including the 55 and 77 grainers?
But there is no chrome lined 1x8 barrel available. Is chrome lining that much more reliable than stainless steel? I am not in the "cat box" nor will I be going. I'm not a competition shooter, yet., but should the Hottintots run amok my rifle would be used as my primary weapon.
55gr is uber cheap, so I shoot it almost exclusively, but I'm geting a lot more serious about my shooting so the 77gr looks real good.
CRAP! Confusion induced anurism!!!!!!
I have a 1x9 BM already, and "one of each" is not an option as I'm in college.
Like friggin help or some junk!!!!!

55gr works just fine in a 1/7 rifle. Either that or my M4s didn't get the memo.

Quoted: 1x7 will stabilize the 77gr but the 55gr is useless in it.

There is no data that says 1/7 cannot shoot 55gr.  The only negative data I've heard about 1/7 and light bullets is it may spin some 40gr bullets too fast and they disintigrate in flight, but thay was exclusive to a couple brands of bullets.

You'll be fine shooting 55gr in a 1/7 barrel and some have shown that 77gr can be shot in 1/9 accurately, but generally there are more problems shooting bullets heavier than 70gr in a 1/9.

Another +1 for the 1 in 7 twist.  If you are at all interested in killing people with your AR, 77 grain offers the best terminal balistics, and the 1 in 7 is the twist you'll need for 77 grain.

The Ammo Oracle

i really wish they made 1x8 or 1x7.7 barrels chromelined...  but they don't....    i have a 1x9 because i mainly shoot 55gr and i wanted  my barrel to last....

i was a little afraid that 1x7 wouldn't work with 55gr was well since i have a 16" barrel...

i do know that if i shoot 75gr out of my 16" barrel... my rounds do very werid things... i'm going to retest this tomarrow

16" chrome lined bbl/chamber 1:7 common upper to find.
shoots 55gr just fine.  no worries

1/7 good from 55 to 77gr

1/7 is the best for 55gr ball & heavier...

As long as you don't plan to shoot the ultra-light (under 55gr) varmint rounds you'll be fine...

Thanks guys. I was feelin crappy about duckin out on the group buy, now I'm back in, and might even get 2. Preciate the hep.