The under lever is a Chinese made B3. They are everywhere. They are usually tack drivers. Mine's 20+ years old, and is my go to gun for garden varmints. Just hold the cocking lever when you reload. The only ones I've heard snapping shut were ones that someone tried to modify the trigger pull. Two or three factories in China crank these things out by the thousands. Usually the ones for export are marginally better than the ones the Chinese can buy, but you need to check them out. Oh, and CLEAN it as soon as you get it.