I might surely attempt them. You can find not cause that they'd not do the job just great within your Beeman. I have had excellent luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin etc.). I'd check out a tin and see how your Grizzly likes them https://jeffreywhtdo.bloggactif.com/37370557/the-5-second-trick-for-super177