AR .22lr Conversion Kit Magazine Legality Questions

[J094]

I recently bought a CMMG .22lr AR conversion kit and it came with a 25 round magazine, and these mags are in stock on a couple sites as well. What I don't understand is how they are legal. The conversion kit and mags can be used in a typical AR pistol, so wouldn't that place these mags in the same category as the 10+ 10/22 mags, making them prohibited devices? As far as I can tell the Kel Tec SU-22 and PLR-22 use these mags as well so I really cannot understand how they are legal at 25 rounds.

I also have a BlackDog Machine 50 round AR drum that is pinned to what appears to be 10 rounds, so if these 25 rounders ARE legal, then what's stopping me from removing the pin on the drum? TrueNorthArms mentioned in a year-old Reddit post that they don't know of any regulation stating they must be pinned but the importer did it anyway.

I'm sure this has been discussed before somewhere, but all I can find anywhere are a few posts from a year ago or like back in 2013.
Need some expert advice here since I'd like to plinking, not to prison

 

[Sniffer]

Can the magazines you are concerned about be used in any pistols?

 

[enefgee]

If the mag is designed for a rimfire pistol it can only hold 10. If it's designed for a rimfire rifle it can hold as many as you want. The mag for an M&P 15/22 is designed and supplied with both the pistol and rifle variants, therefore it can only hold 10. Black Dog mags do not fit or work in the M&P 15/22, so no issue. Black Dog describes its mags as rimfire AR 15 mags, therefore no limit - since BD doesn't make guns, just conversion kits for the "AR platform". As far as the drum goes, I'm guessing - and it is a guess - that the importer didn't want to spend a year or two arguing legality with Customs, and then with the RCMP Lab (who, as we know, aren't the most fact based people on the planet) and have them create another nightmare like the 10/22 regulation, so they had them pinned. Incidentally even with the 10/22 regulation, the instruction to officers is not to lay charges solely based on the 10/22 high cap. this tells me that the lab knows it's on shaky ground and doesn't want this to go in front of the courts where they know they'll probably lose.