I've decided to get an Armalite AR10A4 when I get home in a few months...O.K., four months, but who's counting...

I'm trying to decide between the 16" barrel and the 20" barrel.

My main concern with the 16" barrel is excessive muzzle flash. I've seen some cantelope-sized(Hell, even a few near Basketball-sized...) muzzle flashes from some 16" - 18" barreled .308's and REALLY want to avoid that.

I'm also concerned with more pronounced muzzle flip/jump when compared to the 20" barrel...and, YES, I know it's a .308/7.62mm and has more recoil than a .223/5.56mm...

I'd like to stay with the shorter barrel to save weight, because I've been reading & hearing about how HEAVY AR10's can be.

I guess what I'm trying to find out is:

A) Would a more efficient flash suppressor(i.e. Smith Ent. Vortex) signifcantly reduce or even all but eliminate muzzle flash in the shorter barrel?

B) Is there significantly more muzzle flip or "jump" with the 16" barrel compared to the 20" barrel?

I'd really be interested to hear from folks who have had some experience with AR10's in both barrel lengths...

Thanks in advance!

BTW- I plan on using a 2-optic set-up with this rig...an EO-Tech for up close and a decent mid-power scope for longer ranges. Both will have a QD mount of some sort for quick interchangeability.

I have both a 16in and a 20in upper.  The 16in is configured as a mid-range rifle with an ACOG and a FH, whereas the 20in is my precision ar10 and sports a 10x fixed scope and no FH.

I have not shot them in low light, but have not noticed a significant difference in flash (but only the 16in has a FH) or muzzle flip (but I shoot the 16in off a bipod and the 20in off sandbags/rest).  The 16in is shot more often because I enjoy shooting it more.

Anybody else have any input?

you could get the 20" and see how you like the weight.  the recoil would be easier controlled also.  you can always take a couple inches off.  i heard 18" is short enough.  any shorter the velocity drops fast.  maybe keep an eye out for the rra the next couple months, see what they got.  stay outta trouble.