For this 308ar build. 1st 100rnds fired, i was using the ubr gen2 stock w/ the spacer, aero precision 308 carbine buffer n spring, (cws w/ tungsten 4 ounces). aero non adj gb. Rifle was reliable but not fun to shoot.
Last 200rnds fired. Ubr gen2 stock w/ spacer, kvp 5.6 ounce 2.5 inch buffer. Aero 308 carbine spring. Superlative Arms adj gb set 8 clicks from fully closed. No cws. Alot smoother n easy to shoot now.
I apologize for the confusion.