You will need a mill or a dremmel. My dad did it to one and got it to take take standard mags but had to cut off a good part of the inside part of the rivets and decided to modify a few mags rather than mill off more trunnion/rivit.
When he passed and I ended up with it, I took it to a shop and they milled it a little more and redid the rivets. Now it takes standard mags fine.
Mine has a single stack bolt, but still strips both sides of mag.