And now, "THE REST OF THE STORY", as Paul Harvey would say.
In June of 1991, 1 returned to Molalla, Oregon for another family visit and had time to pursue the "C" drum research a little further. I wrote to Tom Casey at Auto-Ordnance and reluctantly returned my drum #076. He promptly shipped me A/0 "C" drum #025. In his letter he reminded me that A/0 was now installing a new and stronger spring in the rotor. They were also retro fitting earlier drums. This is probably the spring most of the remaining drums out there have in them now today.
He also informed me that he had personally tested a number of drums and this one worked the best. I received this new drum in Oregon in June 1991. 1 promised Casey I would test this new drum as it came in the box from them. I did this.
I promptly took the new Auto-Ordnance, West Hurley "C" drum #025 to the range for testing and fun. I finally had a drum that was going to work. I loaded it with new factory ammo. I then attempted to wind this drum. The key was very stiff and stopped at ten clicks. I felt forcing the key any further would break it. The drum slipped into the 1928A1 Thompson receiver tightly. I pulled the trigger and fired about eighty rounds and then it stopped. There was no spring tension left when I removed the cover. I reloaded and tried a second time. Then I removed the drum and wound it several additional clicks. The drum finished unloading. At least it had finished that far.
I returned home and called Tom Casey at Auto-Ordnance. He assured me that if I just FORCE another click the gun would fire all one hundred rounds out. I asked what about the original fifteen clicks? He informed me that the new main spring would not allow it.
The next time out I put so much pressure on the drum Key I thought sure something should break. With the eleventh click it indeed fired all one hundred rounds out. A second attempt also fired all one hundred rounds. Tom Casey and Auto-Ordnance had fulfilled their promise to me, to provide a drum that would fire one hundred rounds.
I was very unhappy with the test on this new A/0 "C" drum. Eleven clicks on a very stiff spring, and a drum hanging at an angle from the receiver, for $275.00. What did I expect? This is a far cry from an original Colt "C" drum.
There is a principal involved here. The principal is that A/0 insisted these drums were made from the original blueprints, had the same quality and will work just as good as the original Colt "C" drums. The principal I believe is called, "Sow's Ear".
THE EXTRA MILE, for a sow's ear.
So to prove a point, I decided to carry my research the extra mile. Now lets get down to business.
To start with it appears the Cover "slide name plate" is in the wrong place. (See above letter) This causes the bottom of the drum to lean back toward the trigger. This also means the bolt is shelling the rounds out of the top of the drum at a compromising angle downward into the feed ramp. I decided the first correction to make would be to move this "cover slide" name plate. So I drilled out the spot welds and moved the Cover "slide name plate" down about 1/16 of an inch. I had it spot welded back into place. This correction made the drum hang straight. The feed lips were now also closer into the magazine well.
The next big step was to dissemble the rotor and remove the new very thick retro fit spring A/0 had installed. In July 1991, I contacted the Curin Spring Co. of Wilsonville, Oregon (near Portland). The Engineer there examined my A/0 "C" drum. He examined the thick spring which I had removed from the "spring can" under the rotor. Then he asked if I had installed this spring myself I assured him it was the pride of the A/0 factory.
After careful examination of the A/0 "C" drum, the Engineer relayed these facts. The instructions on the Cover "slide plate" say, wind the Key 15 clicks. So 4 clicks = I turn, and 16 clicks = 4 turns. Then 15 clicks = 3 and 3/4 turns. It takes 2 and 1/2 turns to push out all the ammo, leaving 1 and 1/4 turns of tension to provide the extra thrust needed to move the ammo out at a Full Auto cycle rate of fire.