SUPER177 NO FURTHER A MYSTERY

I'd personally unquestionably test them. There is not reason that they would not function just great with your Beeman. I've had superior luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin etcetera.). I would check out a tin and find out how your Grizzly likes them as all guns appear to have their favored pellets.The RWS Superdom