If it's loaded factory ammo I'd definitely take it back where you got it. If handloaded you can pull the bullet and dump the powder. You may want to weigh a charge after pulling the bullet so you can recharge the cases with the same amount. Lube the cases and resize. I'd recommend Hornady One Shot to lube as it won't contaminate the primer or powder. But BEFORE YOU SIZE back off the decapping pin but don't remove completely. You need the expander ball to size the inside of the case mouth on its way out of the die. Just back the decapper out enough so it doesn't contact the bottom of the case (primer).