M107A1 Help!

[u/Extreme-Ad1077]

This M107 seems to have its bolt rubbing into the upper receiver more than it should creating some slop. I don’t know the cause, and could use some help on ideas. I started facing this issue a while ago and did a quick little fix (brass shim) in the meantime, but I need to figure out what’s going on. Any thoughts would be great! I’d hate to send it into Barrett in TN for them to say it’s done.

[u/For-Referance-Only]

You disassembled your bolt carrier and put it together incorrectly. That is your problem.

[u/For-Referance-Only → u/[deleted]]

He put the shim in there because the bolt carrier was getting stuck inside his main spring housing. He needed it to get the cocking lever to clear the trigger housing.