The price is keeping me from trying one. I've got ten 25 round for mine. Keeps me occupied for a couple of minutes
from their website: " New from Black Dog Machine LLC the long awaited S&W M&P 15.22 50 round drum.
These are modified AR15.22 Drums. They have been epoxied for extra strength and then CNC milled to fit in your S&W mag well.
This drum will not work on the 10.22, the Puma/PPS50, M261, nor any other AR15.22 type conversion units."
Where did you see other info.?