Maxim gun
The Caldwell machine gun was designed by Thomas F. Caldwell of Melbourne, who moved to the United Kingdom to bring his invention to the notice of British Army authorities. The weapon was in appearance similar to the Maxim gun, but came with two barrels, capable of working in conjunction or separately with a discharge of 500 rpm. It used pan magazines containing 104 rounds, instead of the belt feed of the Maxim gun which was prone to jamming.