It's a .177 and I'd guess you're right. It shoots fast and there's a telltale crack. Maybe heavier pellets...Yes. Any air rifle that uses a coil spring or gas strut as a power source is a 'springer' (break barrel, under lever, or side lever). The old Gamo's are my favorite and are usually backyard friendly. If you see any smoke in the barrel between shots, then it is dieseling (igniting/burning lube that has gotten in front of the piston seal) and that is likely the loud report. That said, some Gamos are way over sprung and break the sound barrier with light pellets, in which case a heavier pellet should quiet it down.