The HDR 50 (7.5 Jolues) is a revolver with visible strengths – large caliber (.50), enormous muzzle energy and an imposing appearance. The easy-to-load rotary magazine holds six .50-caliber projectiles that are fired at up to 7.5 joules. Power is supplied by a CO2 cartridge located in the grip. A light blow at the bottom suffices to pierce it. The Revolver 50 is ready to use at any time and has full cartridges when you need them. The textured frame surfaces give you a secure grip even in stress situations, and a trigger blade safety prevents accidental firing if you should ever drop the gun.
With Ar-15 conversion kit- you are getting 16J in power!
Basically you are getting two markers in one! its ultra easy to convert back, so you got HDR 50 at UK legal 7.5 J, and once converted to AR-15 it becomes 16J, plus you can mount all kind of accesories, scopes, from handle..etc on multiply picattiny rails the conversion has