A.J. Aubrey had this all figer'd out in 1908
"choke bored on the taper system"
1908 Sears, Roebuck & Co., Chicago, Ill. Catalogue No. 117:
I would very much appreciate if someone with an Aubrey would measure the bore and see if it tapers the full length.
"the choke is bored from breech to muzzle"
Daryl Hallquist has confirmed that an occasional Lefever 12 gauge has bores tapering from the breech to the muzzle (.756 to .708 left and .715 right on one gun). Most have a standard U.S. .729 - .732" parallel bore.
Starting in 1907, Hunter Arms catalogs included the following statement:
"All Smith Guns are bored full choke unless otherwise ordered. We bore all our guns according to our Multiplied Choke Bore System, which has made the Smith Gun famous the world over for long-distance, close-shooting and hard-hitting qualities."
LRWF marketing verbiage in 1923 "A distinctive L.C. Smith method of choking adds 15 to 20 yards to ordinary shotgun range...specially bored to a longer, tapering choke..."
LRWF have bores of .730" without tapering to the choke constriction of about 3 inches in length; slightly more than the standard constriction over about 1 1/2" with a 1" parallel at the muzzle. As noted, some have no parallel section but taper over the length of the constriction.
