I'd personally certainly attempt them. There may be not rationale that they would not operate just wonderful with your Beeman. I have had excellent luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin and so forth.). I would check out a tin and see how your Grizzly https://fernandocoalv.blogdemls.com/35890345/the-greatest-guide-to-super177