The UA-55A is the improved second iteration of the well known bullpup assault rifle made by Universal Arms. Rate of fire is 450 rounds per minute feeding from a 50-round magazine. (The magazine would have to stick out quite a bit unlike on the pictures below of the MA37 from Halo Reach.) The usable cartridges are 6x48 and 7x46 respectively and share the same rim diameter of 10.00mm and have the same total cartridge length of 60mm so all that you would have to do to change the calibre is to switch barrels. (Comes included with every purchase.) There is also an UA-55B semi-auto only variant that comes with a 25-round magazine. The UA-55C is similar to the UA-55B but sports a heavier barrel for serving as a marksman medium range rifle. The UA-55D replaces the flashlight with a 16mm rimless (16x80) scattergun that feeds from a drum magazine that holds twenty-five shells. The UA-55E replaces the flashlight with a 25mm rimless (25x50) grenade launcher that feeds from a box magazine that holds five shells. The UA-55F replaces the flashlight with a flamethrower. The UA-55G replaces the flashlight with a single shot 50mm (50x40R) low-velocity grenade launcher. There are also rumors of an UA-55H variant that replaces the flashlight with a small plasma cannon but that has not been substantiated.