Best left to a trained professional
I would contact Gamo directly for the best answer. See the link below. You do mean "GAMO" not Gamco
Halo 2 has the gravity rifle in it but i (think) you have to have the custom edition to get the gravity rifle.....
Does not exist.
Custom built
QBB-95 is a Chinese light machine gun. QBZ-95 is a Chinese assault rifle.
Custom proposition
Any rifle chambered for that cartridge. Most will be custom made double rifles.
Best left to a professional.
Weing stocks
Usually a custom job these days.
You will have to elaborate. Custom? Factory? Historicaly associated?
I-V and custom