I'd unquestionably try them. There is not purpose that they would not work just fine in your Beeman. I have had great luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin etc.). I would check out a tin and find out how your Grizzly likes them as https://super17700000.blue-blogs.com/43521513/not-known-details-about-super177