I heard about someone back in the 1970s who replaced the barrel of an old .38 Special revolver with a piece of pipe (about an inch-and-a-half or 40 mm) and used .38 blank cartridges to shoot golf balls about a hundred yards.
and you just _know_ some people would be ordering them 6 months before they were available.. .. never mind that to avoid damaging yourself you'd have to load it so light the bullet would be visible in flight - I am sure it would sell.