Browning BAR bolt stopping half way over magazine

[370bc]

I have a Browning Safari II in 270 win that I have replace the inertia piece and slide head bar and cleaning down to removing of the bolt.
After reassembly, the gun dry fires fine, but when the magazine is installed, the bolt stops at the half way point over the magazine.
I have my buddy's almost exact same firearm to compare with. The only thing different I can see is that there is a part sticking out of the back of tjhe bolt on mine that does not on his BAR. About half way though the bolt. I have removed the bolt and reassembled for the second time, only to have the same bolt failure. Any suggestions? Thanks.

 

[370bc]

The timing latch fell back on the bolt during reassembly of the bolt into the receiver. The front of the bolt must extend all of the way constantly during installation. Mine fell back twice. Third time was the charm. Problem solved.