They are a bit hard to find. Saw some on Gun Broker and at a few online stores. Some command high prices particularly Glock 19, and colors FDE and OD green. There is a modification to the G17 model to shorten it 1/4 to 1/2 inch proportionally for standard G-19s to fit. I'm leaning to the G-17 and just buy extra 33 round sticks. The G-17s are more available and often cheaper. Saw IV8888 vids showing it's lethality at 440 yards through ballistic gelatin using both FMJ and various HPs.
A lot of dealers are gouging on the price of them, but a local dealer sells them under $400 and gets them in regularly...