An aside from the original question, but this reminds me of some .243 rounds I loaded years ago. I bought some used .243 dies and they came with an inside neck reamer. I went through my scrap brass bucket and found some other calibers I had thrown out because of split necks, or even any good shells that were convertable to .243. I ended up with 50 rounds with mostly different headstamps; 30-06, 270, 280, 35 Whelen, 25-06, 8mm, 7mm, 308, 7-08, 257 Robt., military headstamps going back to the '20s. They were all sized to .243 Winchester, trimmed to the correct length, inside reamed, and loaded with a mild load that was safe in all the various converted brass.
A friend's younger brother had his eighteenth birthday (a big occasion in their family) and I was invited. Hunting is also big in their family, so as a joke I gave him that ammo for a gift (he used a .243). I heard later that his dad did not like it at all and made him take it up in the hills behind their house and shoot it all up, leaving the brass lie. It seems they had many of those calibers among the large extended family and he was scared to death of a mix up that would blow them all to smithereens.
And any reloader who can't recognise his cartridge without reading the headstamp should not be in the business of shooting anyway.
I agree completely, and would add that anyone who can't tell the difference between a .243 Win and a .35 Whelen shouldn't be hunting with a rifle. However, some folks out there don't know anything about guns beyond making sure the numbers on the cartridge match the numbers on the barrel.