I don’t know why you couldn’t take a old 22cal barrel and ream out the rifling, except the chamber, and put a ‘jug choke’ in the end?
A ‘jug choke’ can make a CYL bore shoot a tighter pattern.
A ‘jug choke’ can make a CYL bore shoot a tighter pattern.
I think it would work. A fair amount of effort.
I don't think you need to ream out the whole bore. The experiment indicates the choke overcomes the rifling effect.
More experiments are ongoing.
I could see barrels that are rifled for 12 inches, and smoothbore, at a larger caliber, say .38 for 12 inches, with a choke on the end, that would shoot both bullets and shot well.
Everything old is new again.
It was called a Routledge bore, and claimed 85% of pellets in a six inch circle at 33 feet!
Very impressive. I would like to duplicate that!
It used a smoothbore from the start, though. During the 1930s, mini-skeet programs utilzing small clay targets were promoted by several firms. One such program was offered by the Routledge Manufacturing Co. of Monroe Mich. In april. 1937 Fred Routledge of that firm applied to the US patent Office for a patent on an invention that "relates to training equipment for skill in marksmanship" His patent application noted the use of a counterbore smoothbore barrel. The cal .22 portion of the bore at the breech end spanned about one-half the length of the barrel. The remaining 12 or 13 inches of the barrel was about 0.40" in diameter. In US patent no. 2,185,523 granted to Routledge on Jan 2, 1940, this counterbored barrel section was claimed to control the pattern of a standard cal .22 long rifle shot cartridge (containing at least 120 #12 pellets) so that 85% of the pellets would strike within a 6" circle at 33 feet.
Between 1945 & 1955 inclusive, Remington produced 2,653 model 121 Fieldmasters and 2,118 model 510 bolt-action single-shot smoothbore guns under the Routledge patent. Also produced by Remington for the Routledge firm were 5,557 model 514 bolt-action single-shot and 3,991 model 572 slide-action rifles with STANDARD (not Routledge) smoothbore barrels.
The above info is from an article that appeared in the November, 1974 issue of American Rifleman.