Credit where it is due sir! Very cool stuff. I've got some of those OpSol adapters, gen 1 and 2 and their complementing follower, but I haven't had the time to test them out. I need to go and have some fun at the range. Life is just work-work-work these days. People seem to have good results with them.

The neat thing about the shorty shells for me is reloading. After a couple reloads of conventional length 12 gauge the shells don't like to take a crimp anymore or are too thin/brittle from the heat exposure, so you just trim off the end and voila! Brand new shells with a primer pocket squeeze, and more reloads, just in a shorter format.

I think I know what shotgun you are talking about, Is this the one? : https://modernfirearms.net/en/shotguns/south-africa-shotguns/mag-7-eng/

You know I've always wanted to learn how to design man. I'm an ideas guy, but I need to try and get involved. I'd love to be able to make my own designs for my saiga 12 and other firearms since it's not a very developed area in the space, a few designs here and there. My idea for your design is to hunt down a double stack mossberg magazine, cut it open and study it's internal geometry and adapt it for the mini shell lengths, but I really like your single stack design as well. I hear you about the open bolt challenges, be careful testing with OOB my friend and stay safe. GOOD LUCK! It's awesome work.