Thank you! I found a previous thread that you had answered I had to use a wooden dowel to press it down and it went right on! Again thank you for the help. My little guy thought he ruined it!Actually, it's the Cocking Lever (not the hinge pin) that's been forced upward due to the hammer being tripped. There shouldn't be any need to do anything with it for reassembly . . . but you'll definitely need to wiggle the forearm into place and press just a little harder than usual to get it on. A lot of guys are justifiably a little nervous the first time they need to do this. It's a common question about the BT-99.
Try it. If you can't get the forearm back on using just a little more force than usual, let me know and we'll go to Plan B.