To a point i'll agree with wjkuleck. Stay away from the Universal design. They LOOK like m1 carbines, but none of the parts interchange except maybe mags. Commercially, the Plainfield design was just like GI, and the current Kahr's are made from Israeli parts. But for what it is-A REPLACEMENT FOR A PISTOL!-it is a decent design. The originals are getting rather pricy when you find them in good original condition. Remember, these were our first foray into what has now become the PDW (personal defense weapon) concept. As such it was designed to be easy to use by someone with much less training than a full power rifle, just like the P90 FN design. The round penetrates better than a subgun, but does not have as much knockdown as 45 rounds. But you can at least hit much farther out with it than you can with a Thompson. And it weighs less than a Thompson making it easy to carry.