In a recent pistol-training.com post, the author begins by stating how finding a good magazine pouch is not as easy as it should be.
https://pistol-training.com/magazine-pouches/
One of hte pouches mentioned is the CCC Basic Magazine Pouch. If I had known that CCC was going to go out of business, I would have bought twice as many of these as I did.
The pouch is made from a single piece of Kydex. An opening down one side of the pouch allows the pouch to flex, but the continuation of the front panel around the bottom of the pouch limits this flexing to maximize the tension with which the magazine is held. That single piece of Kydex was also shaped into a belt loop, which could accommodate a double thickness leather belt, and which could be ordered with 1 1/4, 1 1/2, or 1 3/4 inch width.
Rich of CCC began making this pouch at the request of Todd Green when the original maker stopped making it.
Some Kydex holster maker needs to start making this pouch. I have paid a lot of money for magazine pouches, but have not found a better one.