Came across 3 interesting, and illustrative, images in January 1901 "Outdoor Life"
https://archive.org/details/sim_outdoor-life_1901-01_7_1/page/n47/mode/2up?view=theater

The shoot report is here December 22, 1900 "Sporting Life"
https://digital.la84.org/digital/collection/p17103coll17/id/42597/rec/1

Fred Gilbert's "ready" position. He left Hunter Arms after the 1899 GAH for a Parker, but the gun sure looks to be a sidelock

[Linked Image from photos.smugmug.com]

George Roll with a Remington Hammerless

[Linked Image from photos.smugmug.com]

Dr. Williamson with a Cashmore

[Linked Image from photos.smugmug.com]

BTW October 19, 1895 "Sporting Life"
Dr. J.L. Williamson, of Milwaukee, Wis., has just purchased a new gun of more than ordinary proportions. The Doctor was quite taken with Carver's Cashmore gun, having long barrels and shooting a big load in a 3 1/4 inch shell; but desiring to give the American gunmakers a chance he ordered a gun from the Lefever Arms Company, of Syracuse, N. Y. but at the same time rather doubted their ability to make such a weapon as he desired. However, the gun was furnished and Dr. Williamson killed 79 out of 80 live birds on one trial, and 74 out of 75 targets, part being doubles.
The gun is a Lefever, 12-gauge, weighing 8 1/4 pounds, 32-inch barrels, and chambered for a 3 1/4 inch shell, and guaranteed to stand 4 1/2 Drams of “E.C.” powder, which is the amount of powder which he uses.
(1 1/4 oz. with 3 1/2 Dram “Schultze” was about 12,000 psi. “Schultze” pressures were somewhat lower than “E.C.”)
Dr Williamson did not compete in the 1896 GAH at Live Birds, but held the “E.C.” Cup that year; his gun was not listed
https://digital.la84.org/digital/collection/p17103coll17/id/47243/rec/7
https://digital.la84.org/digital/collection/p17103coll17/id/46882/rec/5
He used a Cashmore with 1 1/4 oz. 3 1/2 Drams DuPont Bulk at the 1897 GAH at Live Birds, and was one of 5 competitors with 24 kills
https://digital.la84.org/digital/collection/p17103coll17/id/45852/rec/4
https://digital.la84.org/digital/collection/p17103coll17/id/46498/rec/3
And at the 1898 GAH
https://digital.la84.org/digital/collection/p17103coll17/id/45659/rec/12
He participated in the 1900 GAH at Live Birds with his Cashmore but used 3 3/4 Drams DuPont Bulk
https://digital.la84.org/digital/collection/p17103coll17/id/42953