The use of 17 and 21 round magazines for these pistols limits what I consider vital practice in changing magazines under stress. Yeah we can count the rounds and put less of them in the mags but this 3D printed magazine block has proved more convenient for me.

https://cults3d.com/en/orders/135082846

I use the 40mm variation which limits the capacity to 10 rounds in an otherwise 17 round magazine. I assume it will take those same 7 rounds out of the 21 round mag and net 14.

I printed mine in white PLA and the white square on the base plate alerts me they're setup for training.

-- Chuck

https://images.cults3d.com/qsH...quare_block_40mm.png

Why not just load 10 rounds?

Or better yet, load some with 7, some with 10, etc. If you really want to take things up a notch throw in a random dummy round- you can load them yourself if you mix them up in your hand and load the mag with yours eyes closed.