Likewise, the ones I shoot the most will not insert into anything else. Years ago I would be careful with mags when I had the Ruger P 94(.40) and P 89(9mm) out at the same time. It took a while, but I figured out the mags are completely interchangeable, in caliber and gun. The only difference is the follower. In fact, I only stock P89 mags now for those two. The 9mm follower lets me load one more in .40 vs the .40 follower.
The only other thing I’ve done is for the ARs, I only use polymer mags for the 5.56. I use steel mags for the 6.8. Not that I have a choice, the 6.8spc won’t fit in a 5.56 polymer mag. OAL is too long.
I did have a range date once that put a .41 round into a .45 colt. She gave it to me when it wouldn’t fire. I blamed that on me, I had too many different calibers out on the table for an inexperienced shooter.