S&W M&P 15-22 .22LR 50rd Black Dog Machine Drum

Drum Features: Built with an interchangeable feed tower, you can easily disassemble the drum, slide your S&W-22 tower out and replace it with the new Black Dog AR-22 or S&W .22 feed towers.
All Black Dog drums are plug and play for semi-auto use. Black Dog Machine does not guarantee that the drum will work in full-auto setups; however, many customers report that with a little fine tuning they can get the drum to work in full-auto.

Recommended ammunition: Federal, CCI/Blazer, American Eagle. Use a round nosed bullet. Stay away from hollow points. Ammunition not listed will not feed well in this drum.
Spring Tension: If you come across feeding issues, the drum spring may be too tight causing ammo to rush up and out of the tower. You may also have feeding issues if the spring is too loose. Spring tension may also be required to adjust to your rifle’s bolt speed. The manual provided will guide you through disassembly and assembly.
Clear Rubber Bands: Each drum is assembled with one clear rubber band and two extra bands taped to the inside of the drum box provided.
Black Dummy Rounds: The plastic black dummy rounds are an important part of the drum assembly. They feed the ammo from the drum body to the tower. BDM does not recommend using dummy rounds as real bullets.
Winding Rotor: Pulling the rotor counter clockwise and letting go will most likely damage the drum. It can cause the internal followers to break.