4. There are many other cartridges that do a better job at either performance or accuracy, or both.
Not everyone
wants 'better performance'; and there is
no evidence that any particular style of cartridge is more inherently accurate than another.
Sometimes, the chosen cartridge is
exactly what the person wants.
1. It's a rimmed cartridge that may not feed well.
3. Did I say it's a rimmed cartridge that may not feed well?
It may not feed well in a stock magazine. However, with modifications, that argument can be thrown out the window. Ever heard of a Mosin Nagant 91/30? M38? M44? Enfield? Winchester 1895? The list goes on...
Rather than telling the poor guy that it's a lost cause; how about explaining what would be involved? That was what he was asking about, anyway.
Abel:
You're looking at major magazine modifications, a bolt face 'opening', extractor/ejector modifications, and a rebarrel job; at minimum. Done cheaply, you'd have probably $500-700 into the rifle, after the purchase price.