Also, please check your owners manual for disengaging RPG launcher when reloading. The previous owner may have emptied the magazine before you acquired the car.
You may have to pull the button out, and twist clockwise or counter clockwise, I don't remember which...
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".