I need 3 of the aluminum block cylinders that S&W (Walter) is using to change the M&P-22 magazines from 12 rounds to 10 rounds. Name your (reasonable) price.

Is there any shop selling them? Shouldn't be to hard to mill them by hundreds.

Note: I know about this but they are not cut at the proper size
Smith & Wesson M&P22 .22 10/12 Magazine Capacity Limiter

Problem solved. These limiters are all over the place at the range :-)

Just pick up a couple of .223 or 5.56 spent cases and use a pipe cutter to cut them at 0.8" (20mm) from the top. Clean them up with your preferred gun solvent, file a bit the edges so they are not sharp and your are done.