The UK is seeing a major shortage of ammunition
This really is something to behold. Based around the TMP9 (Tactical Machine Pistol 9) this has a quite frankly astounding rate of fire, with a sound that has to be heard to be believed (The open fronted metal muzzle amplifies the shots hugely) This uses a 48 BB capacity magazine with side folding stock, 2 20mm R.I.S. rails, adjustable hopup and semi & full auto selectable fire! As this has a metal top slide and will run well on Green Gas with a satisfying crack.
As with all Gas Blow Back weapons performance varies depending on ambient temperature and speed of firing.