[etd]

Problem with a friend's mechbox and from wha he was telling me this is what happened.

He has xyz (the brand) standard ratio gears
I replaced (what he thinks was) a m100 spring to (what I know to have been) an m115 spring.

Now I didn't check his shim job. He says it was perfect and I was in the room when he spent 2-3 hours on it and he tends to be a perfectionist.
Next I installed a better tapper plate spring as I was concerned his was to worn out (the spring was really really weak). We test fired the gun and we both heard the distinct noise of his gears grinding. Now I never touched his gears or his shim job. I told him that he should change his shim job where the sector gear and tapper plate meet as he had different diameter shims everywhere. I explained this may lead to major tappet plate issues as there was a possible catching problem. So he changed everything to be uniform.


So what he states has happened shocked me. Now if what he is saying is true I have a few problems with the logic behind his theories. He went home started trouble shooting. Btw If I'm wrong that's fine I'd rather have a few questions answered and learn a bit more. I find his statements rather impossible:

If you have properly shimmed gears and while closing the mechbox back up.. Let's say the tappet plate got above the shims and was caught between the bushings/shims on the sector gear (this I know is possible). Now "somehow" one of the posts (on the sector gear) pops out of the bushing and goes on an angle and the other post stays in properly with full contact on the bushing. Would you be able to close the mechbox without a fight? Also when you test fired the gun would all of the gear teeth strip before the mechbox seized?

The piston teeth where damaged. Prior to installing anythig he had placed a sorbo pad on the cylinder head and he removed the second piston tooth. He also state she trimmed part of the 3rd tooth down as the engagement was still sketchy.

My theory for the issue is that it's almost impossible to close a properly shimmed gearbox with a gear post all of the way out of the bushing. I find it more likely the xyz gears couldn't handle the new spring or that the shim job enabled to much play causing the bushing to not make snug contact with the gear post/mechbox shell. Both would of my theories would explain the gear shreading. Regaurdless if the gearbox somehow closed without a fight, and a gear post was out of the bushing, this could only happen due to a lack of shims to contain the gears within the bushings correct?