Quote Originally Posted by Mr E View Post
strip the gun turn the receiver upside down and insert just the carrier. it should move freely under its own weight when you tilt the receiver up and down 30 degrees.
now do the same test with the carrier and the bolt. its should lock and unlock just by tilting. the carrier should travel forward until the piston post stops it.
now with a stripped bolt and a dummy round do the test again. with your finger hold the carrier to the rear. insert the dummy into the chamber. tilt the receiver down at 30 degrees and release the carrier. parts should go forward and achieve lock up. unlock should be achieved by tilting up 30 degrees (a slight bump might be needed)
put 2 layers of masking tape on the dummy round and repeat

if you pass all these steps the gun is good. if one of these steps fails then you have a problem
Mr E. ,

Exactly how I check a welded up semi except I add shims to the dummy. You can't use any springs as they will mask any problems.


Joe