More common at higher levels, the 12.7mm submachine gun is a heavy-duty large caliber submachine gun (SMG). It features an unconventional top-mounted magazine, which lies parallel to the weapon's barrel. It boasts a high damage-per-second, but suffers from a small magazine capacity and a fairly large spread, though this spread is still less than that of the 10mm SMG (as of patch 184.108.40.2062). It is also one of only three fully automatic weapons which are capable of being silenced (the 12.7mm SMG suppressor is not to be confused with the 12.7mm submachine gun silencer, as they are not interchangeable), the others being the silenced .22 SMG and Sleepytyme (GRA).
Unlike most other submachine guns, the 12.7mm submachine gun is classified as a two-handed weapon; because of this, traveling with the weapon unholstered will slow the player character's movement speed. This also causes the weapon to be holstered on the back, rather than on the hip as with most SMGs. This also affects it with regard to the Jury Riggingperk, putting it in the same repair class as the service rifle and light machine gun, instead of with one-handed automatics like the 10mm and 9mm SMGs.
Bloodborne cave - behind a very hard locked gate near a trunk holding just under 8000 caps. There is a key to the gate lying by the campfire in the back of the cave (be wary of the tripwire behind the gate).
Great Khans have been observed having the weapon on them in relatively low condition at higher levels.
The weapon's rear sight is actually located on the magazine, a highly unusual feature.
The 12.7mm SMG is one of few weapons that have its own unique reload animation. No other gun has this reload animation and it has no unique counterpart (Other than the GRA 12.7mm submachine gun), making it one of only two weapons to do so (even with full DLC installed).