Here are the benefits of a gas ram over a metal mainspring:
If you're interested in the tactical look, then feast your eyes on the Stoeger ATAC Suppressor air rifle! With a gas ram that will let you keep your gun cocked without worrying about breaking the mainspring, this gun could become your next all-day hunting rifle. It comes with a 4-16x40 scope with an adjustable objective and mil-dot reticle. You can add other optics on the Weaver/Picatinny rails on either side of the forearm. Adding a laser or flashlight will help you acquire your targets in dim light, such as dawn and dusk.