I'd certainly try out them. You can find not rationale that they would not operate just high-quality in the Beeman. I've experienced great luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin and so on.). I would try a tin and see how your Grizzly likes them https://mariowpfvf.liberty-blog.com/36133669/the-fact-about-super177-that-no-one-is-suggesting