I'd unquestionably check out them. There may be not explanation that they might not operate just fine in the Beeman. I've had superior luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin etc.). I'd test a tin and find out how your Grizzly likes them as all guns seem to have their most loved pellets.Umarex 12 Gram CO2 is clean jog