Was the bolt partially closed on the round like a bolt over base malfunction?

Bolt over base malfunctions can be attributed to bad magazines but you ruled that out. I think they can also happen by short-stroking. In extreme cases I believe over-gassing can cause the bolt to outrun the magazine because of the carrier/buffer bouncing off of the inside of the receiver extension - This would also explain why the bolt returned without picking up the next round those 3 or 4 times.
FWIW My BCM 16" middy will run anything with an H3 buffer. It does have over 5k through it though.
Last edited by Eric D.; 08-17-13 at 17:18.
B.A.S. Mechanical Engineering Technology
Bookmarks