Range Day - Happy then Disappointed

[rayman1]

I took my LP08 out to the range today and fired 5 shots through the magazine with AWESOME accuracy at about 20 yards. I really enjoyed it a lot.

Then I decided to load a few rounds in my 1st Model snail drum and was disappointed to see that I couldn't get anymore than one round into the neck of it because it seems the bullet of the Winchester 115gr. 9mm ammunition (and another type I tried) was a bit too long to fit to go all the way down. Or I was doing something wrong and not getting it in there. Stumped on that one.

Anyway, I had the one round in the neck of the snail drum and loaded drum into the pistol but found it wouldn't lock in. After I chambered the one round, the drum locked-in nicely. When I fired the round, somehow the locking bolt and side plate decided to work their way out. The pistol attempted to disassemble itself at that point, I guess.

I've been trying to assemble it using instructions and video on the internet and still cannot get it complete. I can get the upper slid on and the coupler link where it's supposed to be but when I slide the upper assembly back, it will not go all the way back. If I re-assamble everything (locking bolt and plate), the upper is still able to slide around. I'm dumbfounded and hope nothing is messed-up internally but everything appears fine. Any advice?