I was also of the opinion that more than 10 rounds in a pistol was a no go. After dissecting The Act's interpretation and further discovery and seeing a copy of an RCMP letter in this regard, I realized I was wrong.
I have seen and possess a copy of this ruling on RCMP letterhead that our friend achrashb speaks of and I can concur that 14 rounds of 9mm in a .40 cal. magazine according to the RCMP, is absolutely legal. There are no ands, ifs, or butts about the clarity of this letter.
I also concur that my .40 cal. Brigadier and my XD40 magazines accept 9mm ammunition without spewing out rounds when loaded and when smacked in any way as previously mentioned by a member ... and without squeezing/bending lips.
I have not fired this combination in any 9mm pistol as I don't own one of the necessary brands.
With acrashb's permission, and only with his permission, I can post a copy of this letter if he cannot find his copy to do so.
acrashb, please advise via PM if you wish me to proceed.
... and now, if you can all kindly just get along.
Stormbringer, take a deep breath, you're trying too hard.