My very small LGS has AR uppers in 7.62x 39 at a very attractive price. Let's see, I have an AR and a bunch of powder that will work that I'm not ever going to use with I bought it for, plenty of primers, but no dies and no brass, and I have no idea what I would use th caliber for for. I've given up big game hunting because, frankly, I'm not up to it any more. I have better calibers for the varmint hunting I'm able to do, home defense is covered by something I consider much better than a AR----but there is still all that powder sitting there with no use. Gong shooting, maybe, or blowing up water filled soda bottles.
My common sense is probable going to lose in the end and I'm going to wind up with a new upper.