Be wary with glock 22 mags - Tyrant CNC 5 Round Magazine Extension for Glock

Installed two of these onto 15 round Glock 22 mags, .40 cal. While the install was easy (assuming you have the base plate removal tool which you can get on Amazon for 10 bucks), I could not load more than 17 rounds in the mags. I'm also using the new spring included with these baseplates, still no luck. The description advertises 4 extra rounds in .40 cal mags, so this is disappointing. The base plates do look great, are obviously well manufactured, and make the mags drop free easier. Maybe after the new spring breaks in I can fit more rounds, but as they are now it's a bit disappointing. I might buy more for my 9mm mags after a few range visits verify these are reliable.