When I had a PC9 I went to the glock mags and never had an issue. I also was using the .40 S$W glock mags and getting 13 rounds in there on the standard 10 round mag. It was a quick adjust on the steel feeding lips to hold the 9mm round in there without it just slipping out. No problems running these and shot the 1000 round case I bought no problems, before getting tired of the PC9 and moving onto other pursuits.
Yep, for those that are going to ask, this is still legal in canada, as the rules are, "as long as it only holds 10 rounds of the caliber is what meant for" type of thing. Same physical dimensions on the .40 and the 9mm mags, its just the .40 is larger diameter, hence the 3 extra rounds into the 10 rounds .40 mags.
I'm still surprised VERY few people know this, or even go this route. Same cost on the mags, just less mag reloading in the end. Plus it was nice messing with those that have to count your 10 rounds while at the range, and see their faces when you shoot more than 10 without stopping. These guys are out there too!