I say do not use them. In my experience, with different hop up units, bucking, nubs. the crossman BBs either curve wildly, break inside my gun, or jam inside my barrel. They are cheaply manufactured and with that comes lose tolerances (why they get stuck in tight bore barrels), poor materials (sometimes why they break or shatter), or have a high amount of air inside them because of the manufacturing process. (Also why they break from the shock of the gun firing and can explain somewhat why they are wildly unpredictable.) In another note, i know a few people who don't seem to know how to clean and properly lubricate there barrel. I've also been there when they use both the crossman BBs and echo1 BBs. They noticed an increase in there effective range and fewer jams when using the Echo 1 BBs probably because of the coating on the BB and the tighter manufacturing tolerances.