Originally Posted By riflecrank:
The Green Mountain A-1 barrels are outstanding. I have sold over 20 and can't say that I saw one that didn't shoot sub moa groups. They shoot 55 gr bullets like a laser and at maximum velocity and that's what the majority of people fire in their AR-15's anyway. I shoot 50gr Hornady Vmax's in my personal one. The Green Mountain A-1 barrels pops them out at a higher velocity than any other AR I have ever tested, 3400 FPS and the terminal effect is absolutely devastating. Its the perfect walking varmint rig because of the light weight profile. My complete upper with a Clark carbon fiber handguard. weighs only 3.8 lbs and shoots 1/2"@100yds with boring regularity, its my favorite upper.
If I could say that I would only ever shoot 55 gr I'd buy one of those in an instant, I just want to keep my options open for whatever I may need to use.