The Model 1912 is a Browning design; the Model 1911..... isn't.
Well, sort of.
By 1900 Browning and Winchester had parted ways in a dispute over selling the right to a design versus paying royalties for use of a design.
When detail design of the Models 1911 SL and 1912 started Browning was out of the picture at Winchester. However, the core designs of both the Models 1911 SL and 1912 are Browning designs.
For the Model 1912, Winchester started with the Model 1893/1897 core design. Since Winchester owned the design, having bought it from Browning, they were free to do what they wanted with it. Winchester modified the core design and produced the Model 1912. One of the best pump action shotguns ever.
For the Model 1911 SL, Winchester started with the Browning long recoil design. Evidently the Browning long recoil design was not under patent at the time. However, the use of a cocking handle attached to the bolt was under patent to Browning. Winchester needed a work around for the cocking handle. The work around was to grasp the barrel and push it in. Thus, simulating the firing of a round. This action cycled the bolt. This method of cycling the action, if done incorrectly could lead to disastrous results. Thus, the nick name "Widow Maker".
For both the 1911 SL and the 1912 Winchester started with Browning core designs. When Winchester modified and detailed the 1893/1897 design, they got it right, and created the 1912 one of the best pump shotguns ever. When Winchester, using the Browning long recoil core design, and tried to work around the attached bolt handle patent, they got it horrible wrong, and created one of the worst self-loading shotguns ever.
It just seems strange to me that a gun company using the same design approach of modifying a proven design could do so well with one gun and so poorly with the other gun.