Very often, when you buy an older--or rare--semi auto, it comes with only ONE magazine. When you find yourself in this predicament, you are in a bit of a quandary. Where do you go to get additional--or heaven forfend--replacement magazines. For some older guns, magazines are still available. For example, I have been able to find modern manufacture magazines for a p-08 Luger, pre-war Colt Woodsmans, and an S&W 39-2. But for others, life is not so sweet. Original magazines are rare, and really expensive when found. Need a spare for your La Francaise 25 ACP? Good luck! Start haunting Gun Broker, Ebay, and pestering e-gunparts and Jack First. But one source for many odd ball magazines is Triple K of San Diego, CA.
They catalog and make many magazines for guns from manufacturers long since gone, as well as discontinued firearms from companies still in business. But the fly in the ointment is that they often don't work. I ran into this problem recently with three of their magazines. I stumbled upon a Mitchell Arms copy of the High Standard Citation. It takes the military style High Standard Magazine and originals on eBay, if you can find one, run well over 150.00. But Triple K makes them, and I was able to get two for less than 100.00 bucks. That was great.
But the bad news was that neither could be depended upon to feed a round into the chamber. I stumbled through the match using my one good magazine. When I got home, I set to work trying to identify what the root cause was. My calipers quickly gave me the answer when I measured the gap between the feed lips on the factory mag. At the rear, it was ~.178" but at the front, it opened up to about.184. The problematic clones from Triple K had the gap of only .173" and the lips were parallel from rear to front. A cartridge was noticeably lower in the after market mag. This was causing the cartridge to release too late and jamming itself into the edge of the chamber mouth.
In 1974 one of our Regimental Armorers gave me a tutorial on repairing magazine lips. He showed me how to use a pair of pliers to gently tweek the feed lips to return them to correct dimensions. So I took my parallel jawed pliers and applied myself to the task of modifying the recalcitrant magazines. When you are talking just a few thousandths, you have to use a very gentle touch. You want to get it right without bending the lips back and forth. Ideally, you want to bend the metal the absolute minimum to make the change you desire. It only took me about 10 minutes to carefully adjust the two mags to match the factory mag's dimensions, then another 15 to 20 to double check my measurements, and hand cycle a few dummies. I won't be able test fire them until Wednesday, but they seem to be working all right now.
Next is the magazine for my Newly Acquired Remington Model 51 .380.