308 barrel nut shim kitlooks good
.308 Barrel Nut Shim
OK so you're playing with your new build and son-of-a-bee-itch. The hand guard don't fit, the barrel nut, she ain't in the right position. That's OK, these little guys will help more things forward a bit properly without the need to Macgyver a solution. Similarly, if you can't get your gas tube through the barrel nut without uncomfortably exceeding the torque specs, try inserting one or more of these until the alignment gets closer to perfect.
about 0.25mm thick each
|For Receiver Pattern||AR-10/AR-308|