Mine also took a big whack to get off. I disassembled/assembled it 3 times and finally think I get it mastered. After the first whack the 2nd and 3rd barrel release was smooth. I left the scope on but had to re-tighten the screws (this time with some lock-tite. Spent most of the afternoon doing this. It was therapeutic to say the least. Thanks for your reply. Stay Safe.
Congrats on your new 22/45 and for learning early on how to field strip it. For what it's worth (though probably not necessary), I always take my scope or red dot off of my MKIII512 before disassembly.