The Armotech WG-65 is a standard blow back marker that is also a replica of today's M16A2. Unlike the WG-65 M4 version, the A2 comes with a twenty inch barrel that uses VM68II threading. Because of the longer barrel, it allows the shooter fire the marker using tighter groupings due to the distance between the rear and front sights. It comes with a full butt-stock which is very durable. The handguards are also durable and can take a beating for those that like to play rough in their paintball games. Gas wise, it's a big hog when using CO2 and HPA. But that is a given due to the length of the barrel. You might also have trouble in CQB (close-quarter battle) thought. This marker is for the scenario player in mind. Disassembling and reassembling the marker is very easy. The marker should come with a detailed instruction manual that will explain and in's and out's of the WG-65. If it doesn't, then you can easily download a PDF file of the manual which was made by Armotech's own Forum membe