The mags are legal you could even go with a 33 round 9mm glock mag, either mag when brought Canada would be pinned to 10 rounds because it is a pistol magazine. The loop hole here would be just like using a standard .40 Glock 22 magazine in your Glock 17 with 9mm in it. Last time I tired it took 15 rounds of 9mm I think, and its legal to use just like how .50 Beowulf mags can fit more .223/.556
So with a .40 can 22 round magazine pinned to 10 for Canada, I would get the look of the longer mag, and a little added capacity
If you arent familiar with the law here it is read section 5, they actually use a specific gun and the 9mm vs.40 as and example of how its legal
http://www.rcmp-grc.gc.ca/cfp-pcaf/bulletins/bus-ent/20110323-72-eng.htm
Using Glock mags was a big part of my decision to build this, I love my KRISS vector but .45 ACP gets expensive to pop off all day. So I wanted something in 9mm that was like a sub gun, didnt really want to get the KRISS gen2 9mm because I wanted something different. Either way I was gonna go I wanted it to use Gloack mags so I could at least have a 10 round capacity, there were a lot of other cool guns but 5rd capacity because they are registered as rifles killed them for me
And no worries about biting my build, its a very popular build, and I got a ton of ideas from pictures of others builds on Instagram. There is actually a guy I follow whos is almost exactly like mine will be
The business for these builds is supposed to be the Gibbz side charging upper, but QC10 just released their own side charging upper that will be an exact match to their lower, its not available just yet to order but should be soon