I had been thinking about the same thing. About the only good thing to come out of the AWB was to get rid of flash suppressors on match rifles. With the exception of a barrel tensioner or counter weight (whip reduction), anything hanging on the barrel's end reduces accuracy.
I have found that using a peel washer works best for flash suppressor indexing. Peel washers cost more, but, for me, I find them easier to work with.
Are there any National Match modifications to the A2 flash suppressor, such as reaming the inside to a larger diameter? I use a #7 reamer (I think) to open the flash suppressor on an M14. The standard M14 flash suppressor will hold water; when water gets in there, it throws the bullet anywhere but where you are aiming.
I have found that crude accumulates on the muzzle when using a muzzle device. I figure that it blows off when enough gets in there, but it would sure be nice to have a muzzle device that cleaned itself with each shot, just like not having anything there.
Crude at the flash suppressor