Hunters Supply 30 Cal / .310 44 Grain RB These .310 44 Grain RB airgun rounds are cast from a special blend of lead that's hard enough to withstand massive pressure from today's modern big bore airguns, while still being soft enough to facilitate maximum energy transfer on big game. Ideal for targets, varmints and small game. (Please note that all ammo sales are final. No returns accepted for any reason)