0.30g bb pellets are a good weight ammo to use withGood for very powerful sniper rifles, hi end gas pistols and gas rifles ect. a rough guide would be for example airsoft guns that shoot between 400 to 600 fps to use the 0.30g bbs here. we do also sell marking pellets and tracer, glow in the dark & Biodegradable pellets at this weight as well. Need more info? Click here to see our BB Pellet Buying Guide.