These notes were assembled primarily for the benefit of midshipmen who, through lack of time, are obliged to fire at record practice with very little instruction. They are the results of three years' practice, and embody principles essential to good shooting.
Though indoor work requires no change in sight-setting, range work introduces weather conditions that may require constant alterations to keep the center of impact in the bull's-eye. The problem of anticipating these changes is nearly the whole of this great game.
Sight corrections are divided into two classes: (1) vertical, (2) lateral changes. Raising the sight-bar raises the point hit; moving it about its pivot to the right or left moves the point hit in the same direction as the sight motion.
Lateral corrections are the result of three conditions: (1) wind, (2) light, (3) mirage.
A projectile moving in a current of air is carried bodily in the direction of the current, so that it strikes the target down the wind, a distance dependent upon the component of the wind at right angles to the plane of fire. This deflection may be overcome by holding the front sight up the wind on the target, but accuracy requires that the rear sight be moved up the wind according to the graduations on it. For the Krag one point of wind per gauge gives a corresponding distance of 6 inches for every 100 yards of range. For the Springfield smaller sight graduations and shorter time of flight make this distance 4 inches per 100 yards.
Wind force is determined by watching the flags, mirage or anemometer. The farther the flags stand out or the faster the mirage seems to flow, the greater the wind's velocity. The port able anemometer gives the direct reading in miles per hour, for which tables have been computed. Wind direction is given by the azimuth of the flags, by wind clocks, operated by vanes and gear wheels, or by mirage. To the rifleman the range is divided like a clock with the eye at the center. Ahead is 12 o'clock, to the rear 6, to the right 3, and to the left 9. The target is similarly divided with the top as 12 o'clock.
Light affects lateral error by throwing a shadow to one side of the sight, making a rifleman unconsciously hold toward the side of the shadow.
Mirage is the name given to the heat waves which rise from the earth on a hot day. These waves flowing in one direction refract a ray of light from the target, that is, bend it aside, so that the target appears to be down the mirage stream from the position it really occupies. Thus a rifleman does not see the bull’s-eye at all, but instead an image of it. Since he aims at this image he will get a hit distant from the bull’s-eye the same space that the bull’s-eye is apparently moved. A mirage flowing to the left moves the image of the bull’s-eye to the left, and the final result is obviously the same as that of a wind. It is corrected in exactly the same way, moving the sight against the flow of the stream. This mirage was so strong at Camp Perry that it seemed a perfect river, distorting the target into an oval, and almost obscuring it.
Mirage is easily detected through a telescope, slightly out of focus, and is best seen running along the top of the target. The general direction of the wind from right or left may be determined by it, but the flags must be watched also, because mirage and wind at different levels may easily flow in different directions. The mid-range flags should be used, since they give the wind at the height of the maximum ordinate of the trajectory. Mirage is chiefly used, however, to get wind velocity the faster the mirage, the faster the wind blowing it, and the greater must be the lateral correction.
The vertical corrections are made necessary by changes in (1) temperature, (2) barometer, (3) hygrometer, (4) light, (5) wind, (6) mirage. The first three, though factors at long range, are negligible for our purpose. As for light, a bright target and dark sight will usually cause one to aim high for a bright sight and dark target the reverse is true. For this reason care should be taken not to stand so as to throw a shadow on a man's sights, and the shadows of the clouds must be watched carefully. A change from dark to light or vice versa all along the range has little effect. Wind from 12 o'clock retards the bullet in flight and causes it to strike low; wind from 6 o'clock has the opposite effect. Mirage displaces the bull's-eye upward when it flows directly upward, but since it will not run this way long, wait until it shifts to either side to avoid changing the elevation.
Vertical deviation should never be corrected by holding. To change elevation a small amount, the vernier, an instrument so simple as to be readily understood at sight, is used. Its graduations are such that 1 minute of its limb gives 1 inch on the target for every 100 yards in range. To raise 10 inches at 1000 yards, raise by vernier 1 minute. The fact that the 200- and 300-yard bull's-eye are 8 inches in diameter, 500- and 600-yard, 20 inches in diameter, and 800- and 1000-yard, 36 inches, gives a ready means of judging distances on the target.
Upon going on the range, try the trigger pull of the rifles on the rack until a clean, sharp one is found. Fill a belt partly full of ammunition and make it comfortably tight. If a candle is at hand, blacken both sights in the smoke, then go to the firing point and estimate the wind. Set the wind-gauge and clamp it, then set the sight at about 2 x 90 or 180 yards, taking care that it is correct and that the thumb-screw is tight. Now adjust the sling, place the arm in it and assume the easiest position, throwing the hip well forward and resting the elbow in the belt. Draw the hand toward the body to tighten the strap and bring the butt firmly against the shoulder muscles. Glancing through the peep, with the rear sight vertical, bring the front sight accurately in its center, then keeping it there, raise the sight-tip to the bottom of the bull's-eye, 6 o'clock, leaving a white line for definition. Now holding the piece there, hold the breath and squeeze slowly but firmly with the second joint of the index finger against the trigger till it goes off. The sight must be held on during the firing interval to insure a hit.
Suppose the pull was good at 6 o'clock but that the shot hit at the intersection of lines tangent to the top and left edge of the bull's-eye. It is 4 inches out both ways. Since one point of wind gives 12 inches at 200, knock on one-third of a point right wind, and lower the sight the width of a line. If this were the first shot, it may have gone high on account of an oily barrel. Do not change then unless the second shot goes high likewise. Fire 10 shots there for instruction, then 10 for record taking care to squeeze, not pull, the trigger.
Now move to 300 yards slow fire and sit down at an angle with the target, feet well apart and braced. Change the sight-bar to 3 x 90 or 270 yards, and give about one-quarter of a point more wind for the same flags. Take even greater care in holding and fire 10 shots for instruction, then 10 for record.
This completed, take the prone position, flat on the ground, feet well apart, at an angle of 60 with the targets. In both sitting and prone positions move the hand well out along the barrel and get the sling as tight as it can possibly be drawn. Since no sighters are allowed, use the elevation and wind just found. Fire five shots rapid-fire in 30 seconds, then five shots taking all the time necessary to insure perfect aim. These will be marked at the end of each string instead of after each shot as before. Thirty seconds is ample time to fire carefully, and the prone position gives an opportunity of making a high score.
Pistols will now be fired at 15, 25, and 30 yards six shots at each range for instruction and six for record.
If qualified as marksman, a midshipman must make 40 at 500 and 40 at 600 and make a good skirmish run, to qualify. If this run with his marksman's course and rapid-fire pistols aggregates 894 he is a sharpshooter.
Five hundred and 600 yards are quite difficult ranges, requiring close observation of conditions. A good trick here is to get the sight correct for one set of conditions, fire as many shots as possible while they are steady, then if they change wait until they shift back again before finishing the string.
The skirmish run embodies all the principles above set down, and a few more. There are two shots at 600, two at 500, three at 400 and 350, and five from the magazine at 300 and 200. The time allowed is 30 seconds at all ranges except 200, where it is but 20 seconds. Sights are set first for 600 with estimated wind and the elevation previously found for slow fire. To get elevation for 400 yards take the mean of 300 and 500, then halve the difference between 300 and 400 to get 350 yards. The first command is "Fill and cut off magazine," at which five shots are put in the magazine and the cut-off turned down. This is followed by: "Forward, guide center, march, skirmishers, halt. Lie down."
"Fire two rounds at 600 yards" at this command load from the belt, reserving the magazine for 300 yards. "At the targets" aim carefully at the bottom of the big figure "Commence firing" "Cease firing" "Forward, guide center, march" then after 50 yards, "Double time, march" at 500 yards, "Skirmishers halt." In this way the run is carried on from range to range.
Each man fires at a group consisting of a kneeling figure the "squaw" and a prone figure the "papoose." The following points are essential: If you start with more than three-fourths of a point wind knock off one-fourth at 500 and then one-fourth at 400. For each range succeeding knock off one-eighth of a point. If starting with three-fourths or less knock off an eighth at every range. Set the sight in elevation for the next range before advancing at all ranges except 300. Fifty seconds are allowed before "Commence firing" at 200 yards to fill magazines and set sights. Do not fire until the last word of "Commence firing" or the last note of the bugle, and get off all shots before the last note of "Cease firing." Failure to do this involves a penalty of five points. Watch the flags all the time for wind changes. Watch the dirt kicked up behind the target at every shot and hold or change so as to bring the splash behind the target. To verify wind, the first shot may be fired in the dirt at the figure's feet so as to make certain. Fire at the squaw at all except 200 and 300, and if uncertain of your elevations fire at it at all ranges. Make a mental note of ranges so as to get them accurately set for the next run. Hold hard and squeeze the trigger. Keep alert, taking every opportunity to defeat weather-condition changes, and success must surely result.
The above notes give an idea of the points of the game, but of course there are tricks at long-range shooting, many of which were used successfully at the National Match by the team.
The few points above will also serve to show the cause of the fascination that leads thousands of expert riflemen into competition every year. The sport is one of the cleanest of modern games, since it is a test of nerve, skill, and quickness rather than brute strength. What is more it is distinctly in the line of the profession, leading directly up to great-gun practice. To encourage it three medals are awarded to second-classmen for excellence, and sharpshooters' medals are given upon qualification. Once interested in it a man can easily understand the expression of a prominent navy rifleman, and an old Academy athlete, who declared that, outside of great-gun work, rifle shooting is the best of modern sports.