I usually do a couple wraps of electrical tape; when dropping mags I'm prone to step on them(motor skills of a three year old I suppose....), and the tape just keeps that connection intact.
I've found the LAR-10+GS Designs extension is the best, most legal way to run pistol mags, with all the ergonomics of a 5/30 PMag. Mid you, when running range drills, I usually just load my carrier and belt with five mags, with 2-4 rounds each, which forces constant reload drills. I'll often throw a couple empty casings in there to simulate jams & malfunctions, to make training more fruitful.
The ACR in the photos only had like a hundred rounds through it, but my range baby has at least 20k through it now, and I've only had one jam from an improperly seated mag that was covered in dirt. One. All the ACR hate on the intraweb seems to stem from guys who've never had one, can't afford one, or don't know what the "U" and the "S" mean on the gas selector.
I love these things.