I'd undoubtedly try out them. There is not reason that they would not work just fine in your Beeman. I've experienced superior luck with RWS pellets in all of my airguns (Hatsan, Crossman, Benjamin and so on.). I might check out a tin and find out how your Grizzly likes https://super17733332.blogerus.com/57992201/super177-things-to-know-before-you-buy