I’ve seen Glock 17s that have had their grips shortened to accept the shorter Glock 19 mags. It’s not difficult because there aren’t any working parts in the lower part of the grip. I’ve not looked,but I suspect there’s a hammer strut down there somewhere on the CZ hammer fired guns. Is there enough room on the lower portion of a P-09 to shorten it to accept P-07 mags without having to move parts around? I don’t own a P-09 (yet) so I thought I would inquire here to see if it has been done.