Drum beat

[G.T.]

Hi to all, well the relentless repair of Luger drum magazines continues, and I am reminded of the star wars line, "don't get cocky kid!" as I am constantly learning about new and unusual issues concerning function of these monster drums! ....... Todays lesson was an easy one in retrospect, but a seemingly impossible task in reality?
It all starts with two mid to late war original BING drums on my workbench. One is a rusted mess, missing parts, and the other is a less rusted mess, just not put together correctly...
So, lets start with the rusted mess missing parts... easy fix, disassembled the drum, cleaned up all the rust and corrosion, reassembled using NUMRICH reproduction parts (most are exact replacements and work great for repairs!) load up 32 rounds, run thru the bench test twice... winner! The world is correctly spinning on its axis!
OK, on to drum number two, less corrosion, all serviceable parts, just clean lube and test right? Not so fast, in the bench test, loaded fine, but when tested for function jammed on the first and second round immeadiatly!!!! Ok, take apart, clean, polish, lube, same result! Again, clean lube, test, no good! Again, again, again... Auurrrgggghhh! what the hell is going on... am I suddenly struck with stupidity? Or, should I slow down, rethink the issue and start measuring some parts? Well, it turns out, measuring the internal dimension of the mag tube was the key to success.. it measured at .395" and it has to be a minimum of .400" so I made a full length .420" plastic insert and drove it up from the bottom and removed. The spring back saw my final dimension at approx. ,405" and guess what, the drum worked perfectly... First time for that, but I'm sure wont be the last... I'll just be a little quicker to the solution than 4 hours of failed testing... til....lat'r....GT