Get ready for the flames. These guns, as with most of AMT's product line, were hit and miss with regard to quality and reliability. Sometimes, you run across one that works. When you get one of these (and I have one) you realize that, though it is heavy, it excels in its role as a hideout/CCW piece. When you get one that gives you grief, they're the worst POS on the face of the planet. Reliability is the chief complaint from most people. In my view, this design has alot of potential but AMT either couldn't or wouldn't fully develop it into what it could be.
The gun has an extraordinarily heavy trigger. Most estimates are in the 20lb range largely b/c most hobbyists who have triggerpull gauges don't have one heavy enough for accurate measure. It takes a good amount of strength to rack the slide and chamber a round. It's sensitive to even the thought of limpwristing.
There are complaints about accuracy, but you have to realized that this is more likely due to the heavy triggerpull in concert with the gutter sights. This gun lacks conventional sights, instead having a gutter milled in the slide to act as rudimentary sights. Given the purpose of the gun, I think this sort of sight is apropriate.
AMT is long gone, but supposedly High Standard is making them again, along with parts for the old ones. I haven't seen one of the new ones, though.
If the gun you're looking at is a real good price and you don't mind the possibility that you may have to mess around with it to get it working reliably, get it. They're very, very small for the caliber and flat too. I would guess price on a used one should run in the $175-200 range. Maybe $250 for a really pristine example.