The HM-3 is a submachine gun of Mexican origin chambered in the 9mm calibre and, since 2011, in .380 ACP caliber for private security forces, from a magazine fed from the grip, much like the Uzi.
This sub-machine gun is manufactured by Productos Mendoza, S.A. in Mexico. It is a lightweight weapon of reduced overall length achieved by largely extending the wrap around bolt forward around the barrel. A grip safety is provided to prevent accidental discharge. The stock is designed in a manner that makes folding and unfolding easy and provides a foregrip when the stock is folded. The selector lever is on the right-hand side of the weapon so that it can be operated by the right hand without releasing the weapon with either hand. The stock can be folded or unfolded while gripping the weapon with both hands unlike the previous models of the same gun. It is much like the UZI in the way that the magazine is located on the grip.