Looking at building a 22 blaster pistol.

And it seems the only mags to be found are Black Dog sonic mags and CMMG that are 2x much

The black dog mags with steel feed lips work fine in every .22 ar I have.

The older nylon feed lips work well in most of them.

They have been great I have 5 or 6 of them across a couple different.22 conversions

I still have 8 of my original 12 all polymer BDM skinny mags. They run in m16s all day.

Black Dogs work great in my Blaster.

My 3 sonic-x 20s work perfectly.  Two of my three sonic-x 30s would not drop free until the problematic oversized areas were sanded down until they did drop free.  After that, no problems at all.  Everything other than dropping free has been 100%.

+1 on the Black Dog sonic beam welded stainless feed lip magazines...a pair of older screwed together stainless lip mags broke through the top of the mags with hard mag changes, but still function fine as practice mags...I have several older polymer feed lip mags that don't have the time on them that the stainless mags do.... they also work fine, but for a time I used SW 15-22 mags with LRBHO and they wore grooves where the cartridge rim rubbed, so opted to stay with the stainless and forego the LRBHO... as before commented, a spritz of Hornady One Shot dry lube keeps the follower and follower track lubed... I'm shooting about 1200 a month for Steel Challenge, and they are holding up very well

The nylon lips will eventually split, but they warranty them pretty fast.