My LE6920 M4 with a Giessele SSA-E trigger shoots about 1" groups shooting reloaded Sierra 65 grain Spitzer Boat Tail Game Kings. I would like to get it shooting under 1/2" groups.
What barrel do you guys suggest?
If you want a rifle that will "consistently" shoot under a 1/2" @ 100 yds, I suggest you buy a custom barrel mounted on a bolt action rifle, rather than a semi-auto. There are plenty of very good heavy semi-auto barrels, 16" and longer, made by Kreiger, Lilja, Douglas, JP, BCM, WOA, Noveske, Rainier Arms, Compass Lake, just to name a few. But consistent 3/4" groups are a more likely outcome than consistent sub 1/2" groups.
And an accurate AR barrel is more likely to be found chambered with a standard .223 chamber, rather than the common .223 Wylde, or other 5.56mm chambered barrels, like your Colt has. The longer lead built into 5.56MM chambers allows increases in velocity, but does nothing to enhance accuracy.
But a "consistent" 1/2" shooter in an AR with all those moving parts is rather a tall order, and one that requires more than just the fitting of a new barrel.
