NOT KNOWN FACTUAL STATEMENTS ABOUT SUPER177

I'd absolutely test them. You can find not reason that they might not operate just wonderful as part of your Beeman. I've had excellent luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin and so forth.). I'd personally consider a tin and see how your Grizzly likes them as all guns seem to have their preferred pellets.Umarex twelv