The Pedersen device was a top-secret development for the M1903 Springfield in WWI for trench warfare. The bolt of the M1903 was removed and replaced with a unit that fired .30-cal pistol ammo from a top mounted 40-round clip. The device was semi-automatic and had an accurate range of 350 yards. However, it proved difficult to use in the field (imagine performing the conversion in a cold and muddy trench while under fire at night) and was abandoned. It weighed about 3-4 pounds, with loaded magazine (without rifle). Most were destroyed after the war, but a few found their way into the hands of collectors. Others may have gotten lost in battle or transport, or sold off on the black market by military personnel.

All stats are as per M1903 Springfield, except:
Damage Acc 1/2 Dam Max ROF Ammo Min ST Rcl Wt
2d 6 350 1800 ~3 30 11 -1 12.5
Weight includes the rifle.