This is a Daisy Air Rifle known as the 880 chambered in 177PEL, model 990880-603.
The Daisy Powerline 880 Multi-Pump Pneumatic packs a punch - sending a BB or .177 caliber pellet downrange at 800 feet per second. The rifle features a BB reserve that holds 50 BBs" and shoots pellets in single-shot mode. Sturdy and dependable for more than 30 years!
Features:
Caliber: .177 BB and Pellets
Action: Multi-Pump Pneumatic
Powerplant: Spring
Velocity: 800 fps