The Glock G26 can use 10,12,15,17,24, and 33 round 9mm magazines.
A G27 with a G33 and 9mm conversion barrels can use all of the above along with slightly reduced capacity mags in .40 or .357 Sig.
Due to the prevalence of Glocks, Glock clones, and carbines that use Glock mags, I'd guess they...