B&T MP-9

The MP9 is a Swiss submachine gun designed in 2001. The weapon is a development of the Steyr TMP, the design of which was purchased from Steyr in 2001. Brügger & Thomet commenced production of the modified design that same year.

The MP9 utilizes a short recoil operating system with a locking rotating barrel. It is a selective-fire weapon constructed from polymer and corrosion-resistant materials. The design incorporates a stock that folds to the right side, an integrated Picatinny rail, and ghost-ring sights. The mechanism includes three safety systems: an ambidextrous manual safety and fire mode selector, a trigger safety, and a drop safety. It feeds from transparent polymer box magazines. Later production models replaced the original cross-bolt push-button selectors with HK-style ambidextrous selectors. The compact dimensions allow the weapon to be holstered as a machine pistol or personal defense weapon for rapid deployment.

Entering service in 2004, the MP9 has been used in the War in Afghanistan. Adoption includes the Swiss Army, the Indian Army Ghatak Platoons, the Indonesian Navy Denjaka unit, and the French RAID. Other users include the Russian FSB Alpha Group and the Vatican City Swiss Guard. Variants include the NATO-compliant MP9N, the MP45, and the MP9-FX training model. Civilian semi-automatic versions include the TP9, which features an underbarrel Picatinny rail in place of the forward grip, and the TP9-N. The TP9-US is a variant supplied without a stock, while another version was developed requiring only a barrel change to accept alternative ammunition.