M4 Feed Ramp overhang


Active Member
When seating a new (Bravo Co) barrel in a new (Aero) upper, I am noticing the M4 feed ramps in the chamber adapter overhang those cut into the lower. Before you say "lap the receiver," understand I mean it seems the barrel is seating too far into the receiver. I have found information on barrel nut index alignment shims, but it does not seem their purpose is to adjust the depth of the seating of the barrel. They are designed to go between the barrel and nut, not between the barrel and receiver.

I fear this would cause shaving of the bullets or failure to chamber.

What point of reference should I use, or is there a gauge to check proper seating of the barrel in the receiver? If it is seating too far in, what's the fix?


Active Member
bring it over tomorrow.

when we finish cutting trees we will go see if Andy is home.

Andy can fix anything.

(mikey commercial)