I was going to wait til I had the rifle in hand, but this marking has me perplexed. I can find only unanswered posts about it on other forums. It looks to be a WS with the S larger than the W. The closest thing I found was Wilkinson but they are a sword maker. Did they ever have anything to do with rifles? Not that it is their exact marking.
https://www.milsurps.com/images/impo...9095c717-1.jpg