I would certainly test them. You can find not reason that they might not do the job just great in the Beeman. I've had good luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin etc.). I'd personally check out a tin and find out how your Grizzly https://super17777666.blogzet.com/super177-can-be-fun-for-anyone-50783652