I've done a search and there a couple of old threads about STI mags in a Para.
I've picked up a 2nd P18 that has been fitted with a compensator and I'm building it into an open gun, but it only cam with one mag. My other P18 is for IPSC standard and I have some 10 round mags with the 2 Alpha viper bases.
I know I can get a Canyon Creek mag catch to get the STI mags to work, but they won't ship to Australia.
I've picked up a 10 round STI mag for testing.
In the other thread there is mention of welding up the cutout for the mag catch, has anyone that has done this have pictures?
What other options are there?