|The Engineer continued. To have a spring
that would wind 15 or 16 clicks and unwind almost four turns, and still
fit into the original "spring can" under the rotor, it would
have to be 1/32 inch thick and be about 5 and 1/2 feet long. It would have
to be made of the BEST spring steel.
I contracted with the Curin Spring Co. of Wilsonville to make three of these special springs, at a price of $250.00. It was to have a hole in each end for a screw or rivet. The Colt "C" drum has a ratchet assembly on the center hub to keep the spring from bending backwards. The new AO "C" drum has only a rivet through a solid hub in the center to hold the spring in place. It could bend backwards and break.
In October 1991, I received the three new springs. I finally had access to a machine shop on a ship I was working on at the time. In place of the rivet in the center hub, I tapped the hole to 6-32. 1 used a steel screw. I flattened the head slightly allowing for more room around the first coil of spring. The screw was tight but allowed for movement. The other end of the screw was flush with the other side of the hub. On the outside of the "spring can" I used a brass screw with a nut on the outside to hold the outside end of the spring to the spring can. Then I peened the end of the screw slightly. I put the rotor cover, with the fingers, onto the spring can, and placed this inside the drum housing. I blocked the rotor with a dummy round at the feed lips, and wound the spring with the Key to 15 Clicks. The moment of truth. By slowly unwinding the rotor, it unwound 3 and 3/4 turns exactly. The spring was correct.
The Cover still had too much tension against the bottom of the Key. So I tried to take some of the tension out by heating it slightly with a torch. The heat warped the cover badly. I had no choice then but to use a rosebud tip on the torch. I heated the Cover to red hot on a steel bench. By using the proper weights and hammers I brought the shape of the cover back to where I had wanted it in the first place. The last thing I did was to pack the spring can with medium grease and have the rotor spot welded back onto the spring can.
In the spring of 1992, I again took the Auto-Ordnance "C" drum back to Molalla, Oregon for testing. I loaded six dummy rounds into the center of the rotor and then turned it until the rounds reached the feed lips. This was to tune it and make sure there were no tight spots in the guide rails. I wish I could say at this point that there would be a happy ending.
The grand test. The final moment was here after 1 1/2 years. I loaded the drum with one hundred rounds of shiny new factory ammunition. I knew this would be a proud moment worth waiting for. I wound the Key 16 clicks to be sure. I slipped the drum into the Thompson, heard it latch, and pulled the trigger. The drum functioned but it would only push out about eighty rounds on an initial trigger pull. Then the bolt failed once again to pick up. Repeated attempts yielded the same results. Sometimes more and sometimes less would fire out.
When I switched to semi-auto the drum would feed and fire all day. But wasn't the drum designed by Auto-Ordnance to fire on Full Auto? I even tried winding the Key to the full 18 clicks, as far as it would go, with only the same results. At that moment it began to rain.
My final conclusions are:
After making major upgrades to the Auto-Ordnance "C" drum, it will still only function on semiautomatic, even though the spring tension is correct at this time. With one hundred rounds of .45 ACP in the drum, there is still too much internal resistance to keep up with Full Automatic fire. Contributing factors could be; the length of the new spring, or the grease in the spring can, or the layout of the rotor arms in relation to the internal cartridge guides could also be incorrect, causing binding or friction.
The "slide plates" back and front are not correct and are leftovers, as is the center hub. The clearances are so loose it renders this drum magazine next to useless. These A/0 "C" drum magazines cannot even be used as shooters, let alone collectors. These will plague the collectors world for years to come by unsuspecting people.
What governed the Auto-Ordnance production was "cost cutting", not quality control nor making a product that worked. The question was, can we fool the public with a sow's ear, instead of a silk purse?
The whole point seems to be that this A/0 "C" drum is at best a design flaw, and at worst a fraud to the public.
For you Thompson guys out there, who like myself wanted a "C" drum for less, $275,00 [original price], is too much to pay for a wall hanger or a static display. The thrill of buying something for less is far overshadowed by the time and frustration spent on poor, very poor quality. Buy an original, pay the price.