[Scorch]

Your rifle is a commercial Mauser 98 variant made on an FN commercial Mauser 98 action. The double triggers are called "double set triggers" (as opposed to a single set trigger). The rifle can be fired using the front trigger alone, or (for a supported, well aimed shot) the normal trigger pull can be substantially reduced by "setting" the rear trigger prior to firing the rifle (again using the front trigger). Set triggers are common on European hunting rifles, not so much on hunting rifles in the USA. Another clue that it was originally a European hunting rifle are the scope mounts, claw mounts and front bell mounts are almost exclusively a European thing.

The recoil pad is a Pachmayer recoil pad, and was installed by a gunsmith in order to reduce the felt recoil when firing the rifle.

All this still does not tell you what cartridge your rifle is chambered to fire. A gunsmith can help you out by doing a chamber cast if the barrel is unmarked.