I would undoubtedly try them. There's not purpose that they might not do the job just great inside your Beeman. I have experienced fantastic luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin etcetera.). I would try a tin and find out how your Grizzly likes them https://franciscohvhsc.iyublog.com/35070329/top-super177-secrets