@M4rk @siesmith87
Sie was closer with mentioning a Proto Rail, however just for reference please note that 'marker' is a term used for a paintball gun, originating from the paintball guns initial purpose of forestry and livestock marking particularly with regard to early paint which was oil based and designed to stay on what it was shot at - literally marking trees and livestock
As time progressed and paintball became established as a game oil based paint began to be avoided so that it could be washed off and to reduce staining
A hopper can be defined as 'a container for a loose bulk material such as grain, rock, or rubbish, typically one that tapers downward and is able to discharge its contents at the bottom'
It should not be hard to identify why typical loader in paintball are refered to as hoppers
A rotor and a halo too are not markers!