Some good ideas here.
Lets take the Onotari Rhino Hunter (the rifle in question originally) and apply some of these suggestions to it. I assume that the high damage of the weapon is set to reflect the HPC in the description. Do you think, then, that the weapon could potentially fire normal rounds, but -2 damage?
Or would you take a simpler route and just say that if I own the license(s) to make it legal for me to carry this weapon I could potentially obtain a license to carry the ammunition for it?
Seems like 2 viable options, and we have enough heads here to posit a reasonable decision ... so whatever the community decides will become a house-rule at our table.
I'd go for the path that if you have the licence for the rifle, you have a licence to purchase ammunition too. Apart from the collector's licence down here, most licences assume that you will be firing it and so need to buy ammunition for it.
