another idea, the unstackable weapons of 1 type should be limited to 5 (different type of deterrioration of course 100% new ones stack). Theres no point in greater number.
Bad idea. Guns are useful and five can be bought within ten minutes and then you're left with going to another town because the remaining 15 someone sold were deleted.Why not make radios "bad" like brahmin shit so that you can't sell them? Brass knuckles (if you are strong), weak healing powder (if you are smart), rope (if you have high endurance and generally travel) are good alternatives that do stack and don't cause as many problems for shop-goers.
I don't think weapons can stack at all. But preventing selling radios is a quick and painful way of helping with flooded shops.
If you want to make enemies, try to change something.
Radios are produced at $2000 an hour, they are no more or less profitable than any other level 0 item. Seems to be a leftover from the early, unbalanced system when radios actually were good to craft.