American military locks

[Raymond]

I have been having an extremely difficult time picking some new American 5200 locks with the Master keyway. I am only successful on one out of ten. I have taken one apart and found NO spools or grooves on top or bottom pins. It is a 5-pin lock, sloppy tolerances, crimped plug retainer, and generally not of high quality. BUT, it has one bump resistant type pin that has a sharp groove on the end. The pin tip with the groove goes into the plug but the remainder of the pin is too large a diameter to enter the plug. The bump stopper pin is not touching the bottom pin until the bottom pin is lifted to just below shear. I have tried spp to locate the one bottom pin with no spring pressure which would indicate the space of the bump stopper. This promises to be the best solution but I'm still not having good results. It doesn't matter whether I use top or bottom of the keyway turning pressure. Anyone with fresh ideas?

[landeroth]

may sound stupid, but here is what i do on every lock... i try to keep track of each pin i set, so that i know which ones will be left. ie, i set pin 3, so that leaves 4,2,1... and i then lift all three stacks slightly to see which has the most resistance. Now to get to where that would apply to that lock.. i would ignore the fact that it doesn't contact the bottom pin until it almost reaches the shearline. just treat it like a lock with a kinda sticky top pin. ( i have a couple that pull that stunt). that pin will eventually have a place in the binding order, and remember, it was built by the lowest bidder so you can and will do it if you don't give up.