Check out the beautiful 9RS Reverse Stretch Pistol from PTR (w/ included SB brace). It's a semi-automatic, roller delayed blowback reverse stretch 9MM pistol w/ 6inch barrel with tri lug 1/2x28 adapter. This model inparticular sports the compact MP5 front end w/ a full size rear. Some of the other neat features include an MLOK compatible aluminum handguard & a precision welded top rail that makes it possible users to mount a wide swath of optics.