I'd surely try out them. There may be not cause that they might not do the job just high-quality within your Beeman. I've had good luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin and many others.). I'd try a tin and find out how your Grizzly likes them as all guns seem to have their favorite pellets.Umarex twelve Gram CO2 is