The aiming-disc is a small rod, bearing a disc of metal or cardboard, painted white, about 1½ inches in diameter (Fig. 66). On the front is a black bull’s-eye ½ inch in diameter, in the centre of which is pierced a hole just large enough to admit the point of a pencil. On the back is a bull’s-eye, also ½ inch in diameter, placed so that the six o’clock line is just above the hole which is in the centre of the bull’s-eye on the front. [Illustration: =Fig. 66.=--AIMING-DISC.] The instructor may ascertain the accuracy of the recruit’s aim and his power to press the trigger without disturbing aim by the use of the aiming-disc in the following manner: He should take up his position in front of the recruit at a distance of about 4 or 5 feet from the muzzle of his rifle when held to the shoulder for firing in the lying position, with his eye to the hole in front of the disc (Fig. 19). The recruit is then instructed to bring the rifle to his shoulder for aiming, to aim and press the trigger at the aiming-mark at the back of the disc. Through the aperture at the bottom of the bull’s-eye at which the recruit takes aim and snaps, the instructor is able to see the recruit’s faults of aim, and to note whether his aim is disturbed when the trigger is pressed. The instructor is also enabled to note the rapidity with which he takes aim and presses the trigger.--This practice is useful to develop in men the power of aiming rapidly and correctly, which is essential for snapshooting and rapid firing, without the danger of their contracting bad or careless habits through hurried movements. V. “HARMONIZING” RIFLES FOR MINIATURE RANGE PRACTICES. =1.= Rifles are said to be harmonized when their slight individual differences in shooting are corrected by adjustment of sights. This harmonizing or correction of differences in the shooting of the rifles used in miniature range practices is necessary to obtain satisfactory results. _Rifles must be harmonized for firing direct at targets as well as for firing with elevation_, as in landscape practices. With reference to direct firing at targets, it has been found that with service rifles an elevation of 300 yards is necessary to obtain the greatest possible accuracy. Consequently, rifles must be sighted for 300 _yards_ before being harmonized for firing direct at targets according to the method described in the following paragraph, aim being taken at the aiming-marks on the _lower_ horizontal line, and differences being discovered by the grouping of shots on the aiming-marks--not on the line above. The sighting necessary to correct differences in each rifle will also be recorded on a board hung for reference on the miniature range, as described in para. 3.