Mike:
It seems a lot of rook rifles were bored to .410 or relined to .22 rf. I suspect it might have as much to do with practicality as with gun laws, although the latter is certainly a player. It could well be that with a growing population a .22 or .410 would be a more practical firearm than the larger cartridges such as the .360.
The good news is that you get a great rifle to restore as you see fit. The proverbial Silver Lining. Best of luck on the project! They really are wonderful little rifles.
Glenn
