Double rook rifles are very rare. Most were singles. It was common practice here in the U.K. for them to be bored out to .410 but they then usually had the end 3/4 of the barrel turned down from the octagonal to the round to better balance them. If still o.k. but with poor bores it can often be re-lined. Most former .300's are best lined to .32 S&W Long which has similar ballistics. The .360's can be relined for a .38 Special round but loaded light to give similar results to the original. Ironic that the old original rook rifles are now worth about four times what they are when taken to .410. This was done as ammo became scarce. I have one so converted that, according to the proof marks, was done in 1939/40. Lagopus…..
