Considering the fact that your 22 brief magazine has no markings It is far from from Winchester. I have never observed a 22 short magazine which was not a similar outside dimension as 22lr mag. I can’t imagine how a mag, like you described, could chance be protected when inserted. https://highimpactrounds.com/product/winchester-defender-segmented-slug-12-ga-2-75-in-1-oz-1600-fps-10-rd-box/