Since your 22 small magazine has no markings It's not necessarily from Winchester. I have never found a 22 small magazine which was not the identical outside the house dimension as 22lr mag. I'm able to’t imagine how a mag, such as you described, could probability be secure when inserted. https://highimpactrounds.com/product/winchester-super-x-12ga-2-75in-1oz-6-lead-shot-1290fps-25-rd-bx/