It was a good read.
I have since the 70's used a CO2 pellet gun til the seals leaked badly
I used a Crosman 38c which is the exact replica of a S&W model 15.
I need to get one for my MOD-2 Compact.
My muscle memory and sight acquisition was amazing when I used it regularly.
I recommend it you can do it anywhere when range time is not possible and it is very economical.