I bought one just for the heck of it. Put just over 300 rounds through this morning. Functioned flawlessly.
Why would you need a 21 round mag? I suspect competition more than likely. I know several people that have wished Glock would make a 9MM magazine between 17 and 33 rounds.
As you can see by the pics, the magazine sticks out quite a ways on my G19. But nothing like the 33 round mag does.
It seems as though everybody and their brother is making aftermarket Glock mags these days. Some good. Some bad. Others yet to be proven. But IMO OEM Glock mags will always be the best.
Magpul Glock 9MM 21 Round Magazine
Linear Mode
