Several of our makers in the 1930s and 40s provided chokes similar to Winchester's WS-1 on their skeet guns. The Remington Arms Co., Inc. SKEET chokes on the SPORTSMAN autoloaders, Model 31 pumps and Model 32 over/unders all have the flare. The "Skeet Cylinder" choke in the right barrel of Savage's Ansley H. Fox skeet guns have the flare. Ithaca Gun Co. had this drawing --

[Linked Image from i.imgur.com]

but neither of the Ithaca double skeet guns I have are so choked.