I just obtained 8 of these G26 pmags and tested them for function in my Gen 3 G26. They all ran without a problem in feeding. Getting the 12th round in the mag was tough. An additional note which is common with OEM mags was seating the mag with the slide forward required extract attention - more so than OEM types. I have run G17 mags and G19 as well as the 21 rounders. I have had no issues. I particularly like the ease of breaking them down for cleaning. You can use a 9mm bullet to take it down. I like them.