Thumb Savers...
Neat idea!
Another option is a 1" wooden dowel, with a nail sticking out a 1/2" or so. (Just dull the sharp end...) Put the nail in the hole in the follower, and thumb it down easily.
T/C sells a similar device for their 10-round mags for the 22 Classics/Benchmarks, as they are a BEAR to load after 5 rounds are in... Most T/C shooters found a way to make their own for lots less.
By the way, as T/C and S&W have common ownership now, and by me owning both a Classic and M&P15-22, I can see a lot of similarities in the design of the mags.
Of course, the BIG difference in the two is that T/C actually sells a SHORT 5-round mag for their semi-auto 22.
Tight groups.
Old No7