I have a Raptor 40 and a MK9K in .40 that I use with my subguns with 3-lug mounts. The "piston", Gemtech's term for the part in the mount that goes over the muzzle, can be changed for use with 9mm 3-lug. I've posted the difference between the .40 caliber and 9mm mounts here in the NFA section. I need to compare my .40 caliber MK9K to my brother's 9mm MK9K in 9mm. Dr. Dater said that there shouldn't be any appreciable sound difference. Since my brother lives in Arlington, VA and I live in Las Vegas, NV, we have had trouble lining that up. I know it is not the info you were looking for, but I'm very happy with my Raptor 40 can. I not aware of another .40 caliber subgun can with a 3-lug mount. The Raptor 40 is full auto rated with full power 10mm Auto. At least now you have another post.