(f) Both service and blank ammunition should never be carried in the battery at the same time. If conditions are such that both may be used in exercises, only one kind should be in the firing battery; the other should be under lock and key outside the firing position. (g) Misfires and hangfires are of exceedingly rare occurrence. In case of a failure to fire, the firing handle should be pulled again in order to snap the trigger. If this fails to fire, the breech should _not be opened_ until after the expiration of at least one minute, when the round or cartridge should be removed and placed to one side. Defective ammunition, cartridges and primers should be reported. With Blank Ammunition. Firing with blank ammunition will be greatly facilitated by a careful observance of the following: (a) Before firing, a careful examination should be made of the assembled rounds to see that the felt wads have not become displaced or the cartridge cases dented or deformed by careless handling. If the cartridge cases have been properly resized and are clean, no difficulty should be experienced in inserting them in the gun, provided the chamber of the latter is clean. The continued insertion of cartridge cases that are not clean causes an accumulation in the gun chamber which may make the insertion of subsequent rounds difficult or impossible. (b) In firing blank ammunition the gun chamber will be sponged after each round with a damp sponge, to extinguish sparks and remove powder residue resulting from the previous round, before the insertion of another round. (c) Care will be taken to see that the sponges are not worn and that they thoroughly fit the chamber. The interval between rounds in firing blank ammunition should be sufficient to allow thorough sponging of the chamber and examination to ascertain that all sparks have been extinguished. (d) Wads for the preparation of blank metallic ammunition are made to tightly fit in the cartridge case. No wads should be used that are not a tight fit in the case. FUZES.