Description The MONTGO-9 blowback 9mm AR upper receiver, with NO BUFFER! Compatible with any AR-15* and/or AR-9 lower (magazines for Glock® 17 & 19 OR Sig Sauer® P320™), the Montgo-9 gives shooters endless build possibilities while being compact and versatile. Solid end receiver…does not require a buffer Hard anodized billet aluminum 5.5” barrel, 4140 Nitrided ½x28″ threaded barrel Full length integral picatinny rail for installing optics or sights 3.5” bottom picatinny accessory rail Non-reciprocating charging handle…can be used on right or left side 4140 steel nitrided bolt & trunnion for durability No tools required for field stripping OAL: 12.125”, Width: 1.47”, Weight: 3.5lbs *AR-15 lowers will require the MagX adapter (or similar) to accept 9mm pistol magazines.  We recommend using a standard AR-15/AR-9 trigger system, and not binary or FRT triggers.  We do not recommend running the Montgo-9 in full auto.