Say what? Just what in sam hill do they think is inside those copper jackets? Cream of wheat? Freaken dumb as dirt bureaucrats did this! Anyway, if you really have no where else to hunt, there were some sabots made for shooting modern bullets, kind of like the old accelerator loads. They may work in your gun, if the rifling isn't too deep.
With all the crap the gov't does, release of tear gas in training, firing shells, exhaust pollution, what about the copper pollution from jacketed bullets. etc, they are worried about 2 lbs of lead being deposited annually on how many acres?