I have one of these as well, got mine used. It came with 40 and 9mm barrels and bolt faces. Uses Glock mags, we have Glock 40 caliber pistols so lots of mags. The only down side the rifle does not like knock off mags, but factory Glock mags work great. Trigger is a bit off but workable. Feed ramp needs a bit of polishing, FMJ shot great, cast would hang from time to time.
Something else, mine came with out sights, I have a set of cheap folding sights on mine. After a few sight in shots it hit where we aimed it. I had been looking for a carbine in 40S&W for a good bit, this popped up and I took it. The barrel comes of and back on in less than a NY min. LOL makes for putting it in a bag to carry easy. Barrel would easy to thread for a can.