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.
2. Method of Harmonizing Rifles (see sky screen, [Fig. 58]).—(i) The following is the method of harmonizing rifles: The rifles selected for miniature range practices must be numbered from 1 on consecutively. Each rifle must be marked with its number. When this is done, a horizontal line must be drawn along the bottom of the blank sky screen. At intervals of about 12 inches along this horizontal line a number of aiming-marks must be painted. The number of aiming-marks must equal that of the rifles to be harmonized, so that there is one aiming-mark for each rifle. At a distance of 26½ inches above the line of aiming-marks another horizontal line must be drawn on the sky screen, which must be visible from the firing-point. This distance has been chosen because it is sufficient to cause shots aimed at objectives at the bottom of the landscape to clear the top of it and strike the sky screen.
(ii) Harmonizing Rifles for Elevation.—Each rifle will then be adjusted for 1,200 yards. Each rifle, thus sighted, will be fired by a reliable shot with regular aim at one of the aiming-marks. The sights of each rifle will be adjusted until shots which strike above or below the upper horizontal line on the sky screen (when it is sighted for 1,200 yards) strike the line itself. When shots fired from all the rifles strike the line after sights have been adjusted in this manner, they are said to be harmonized.
3. Record of Sighting.—The variations of each rifle, if any, from the original sighting at 1,200 yards—or 300 yards in the case of sighting for direct hits—will be noted, and its variations written down for reference against the number of the rifle on a board to be hung on the wall of the miniature range. The following is an example of the record of sighting:
| Rifle. | Elevation for Direct Hits. | Elevation for Landscape Targets. |
|---|---|---|
| 1 | 300 | 1,200 |
| 2 | 300 | 1,200 |
| 3 | 350 | 1,250 |
| 4 | 250 | 1,150 |