Here is what I posted in that other thread:
"You have to consider how desirable a rifle for an unusual cartridge may be to others. You have built your rifle, and may have no thought of selling it. But you wouldn't like to think of it being left in a corner to rust a couple of generations from now, because it is for no available ammunition or loading equipment.
We don't know why the .22CCM was made larger in diameter than the WRM, but I don't think it was likely to be the existence, or former existence, of the Velo Dog. One possibility was that there were Magnum firearms convertible simply by a change or block, which were unsuitable for the higher pressures to which some might load the CCM. It may also have been that it was considered advisable to have a little more thickness of metal around the primer pocket.
I've mentioned this here before, but I have a large quantity of Winchester Super-X headstamped rimfire cases an inch in length, of standard LR diameter but never loaded, which I bought on eBay for making bullet jackets. The only thing I know of that they might have been meant for is shotshells. Although they thicken slightly as you approach the rim, I think a large pistol primer could be rammed all the way down, and the anvil held in place with a superglued or crimped diaphragm made with another one."
It isn't Magnum diameter, and the firing-pin would have to dent the primer through the case head. But many rifles give a stronger firing-pin blow than a pistol. You would need a heel bullet unless you adapted it to a .20 barrel, but one for the .297/.230 is available from
http://www.castbulletengineering.com...fle/22-calibre in Australia.