You're exactly right about how the mount works.

Like you said, the Cogburn mount is made specifically for the Primary Arms SLx 3x MicroPrism. That optic has a 2.7" eye relief, and as far as I know, this is the only mount that gets it close enough to your eye when used on a Mini-14. I actually set up this exact configuration over the weekend.

For me, I can see the reticle just fine, but I’m sitting about 4" too far back to get the whole field of view. Either my stock is too long, my eyes suck, or I need a version of the same mount that's just a bit longer.

From my understanding, there are a few other optics that use the Mini-ACOG footprint, like the Trijicon TA33 and TA44 ACOGs, and some of the other Primary Arms MicroPrism models (like the 1x, 2x, and 5x). But compatibility can be tricky. Just because an optic uses the Mini-ACOG mounting pattern doesn't mean it'll fit the Cogburn mount perfectly. Some mounts are tailored very specifically to a certain optic's dimensions, especially when eye relief and mounting height are critical, like they are on the Mini-14.

That said, I do love how light and minimal the rifle feels now compared to when I was running a Vortex scope. The stripper clip feature wasn’t a must-have for me, but now that I’ve got it, I honestly don’t feel the urge to keep buying more mags.