[delta76]

Because of the reinforcement bars at the front of the shell, sliding the box into the upper receiver is difficult, it is insanely tight, not tight enough that you have to force it in, but the clearance on either side is less than half a millimeter. There were a couple imperfections on the inside of the upper receiver that needed to be shaved because the front of the box would not move past (sliding the box in backward did not pose the same problem indicating that it is indeed the reinforcement bars that cause the problem). Also, when inserting the box, the reinforcement bars cause a slight elevation which causes the top of the box to contact and jam against the charging handle which makes it impossible to insert with the charging handle in place; so I had to dremel the charging handle as well.

Also I should note that I haven't installed the selector plate or inserted the body pins as of yet so I can't guarantee that I'm totally out of the woods on this one. Also I was wondering if anyone could inform me on how to remove the nuts on a SMOOTH gearset so that I can change the bearings to 7mm bushings. The FTK kit I bought came with 1 gear key and I'm starting to think that it is not enough to properly disassemble (also I think the nuts are thread locked in place) any suggestions? The instructions indicate that the single gear key provided sufficient to remove the nuts but since the axle is threaded on both ends I don't see how this is possible.