A very nice weapon. Just a bit more info for you on the open bolt system of firing. It means that a round is only stripped from the magazine or belt at the moment the trigger is squeezed. It is only then that the bolt moves forward, chambers the round and fires it. Tremendous heat builds up on the chamber of a machine-gun, and if the gun were to fire on a closed bolt system, there is the risk of the round cooking off.
Maxim-type Mg's worked off the closed bolt system. That means that the round in the chamber was only fired when the trigger is squeezed. The weapon had to be cocked twice before a round was placed in the breech. It was not uncommon to get a runaway gun through overheating, and the only safe way of stopping it was to take some rounds out of the belt or cut the belt. This is one of the reasons that Maxims were water-cooled, it was an attempt to keep the barrel and the breech cool.