decoding serial numbers

Made in California. Originally AMT was Arcadia Machine and Tool. Seems like they went out of business and were taken over at least three times (possibly more). Each new owner kept the AMT name, so you're not really sure what you have, in terms of quality.

Having said that, I have a couple of AMTs. My Hardballer frame (I just bought the frame, and built a gun on it) is A17xxx, and I bought it in '83. I've had no problems with it. My other one is a CM serial, and was bought in '99. It's not as good.

I was hoping to find out how old it is?

Well, that's why I posted my two. My "A prefix" number was from '83, while my "C prefix" number was from 99. That gives you a 16-years spread from where your "B prefix" number was probably made. Narrows it down more than what you did know, doesn't it?

yeah I suppose, when did they stop making the hardballer? I noticed the trigger on mine is different than every picture ive seen. Mine has three holes in the trigger and every picture is an olongated hole.