The String Test Measure for Historical Target Practice

I have added a video showing how to calculate and use the String Test.  It can be found HERE.

Men have devised numerous methods for judging accuracy in target shooting over the years, but for the proponent of historical shooting using a method common in the period of the shooter’s interest gives an added dimension to the sport.  Methods can be as simple as determining which shooter can come closest to a given mark, or as complicated as the Figure of Merit system used in Victorian England (see HERE).  Several Nineteenth-century American sources refer to the String Test system, and it is this method which we will examine here.  It is simple, easy to do, and gives a single numerical score which can be used to track both group size and zero.

Terminology
We need to define several terms in order to discuss this subject:
Mean Point of Impact (MPI):  The average of the group where the shots actually hit; group center.
Intended Mean Point of Impact (IMPI):  Where the shot group was intended to be centered.  Also called “Correct Zero Point.”
Grouping:  Adjusting the ammunition, sights, sight picture, and point of aim so that the group size is as small as possible.
Zeroing:  Adjusting the ammunition, sights, sight picture, and point of aim so that the MPI moves to your IMPI.

What is Accuracy?
Ultimately, a shooter wants to be able to hit the target for which he aims, and that seems simple enough.  When considering a series of shots, however, there are two factors which really matter:  The first is the size of the group of shots, and the second is how close those shots come to the bullseye; in other words, how close is the MPI to the IMPI?  Modern shooters often focus exclusively on group size, but this ignores how close that group comes to where it was intended to go.  The String Test considers both factors by measuring the average distance of each round from the bullseye, which quantifies both grouping and zeroing in a single figure.

Historical Use of the String Test
The Berdan Sharpshooters were elite Federal light infantry of the Civil War.  They were principally armed with the Sharps Rifle (a rifle version of the Sharps carbine used by the cavalry).  In order to qualify for these units, applicants were told to fire a string of ten shots at a two-hundred-yard target.  The average distance could not exceed five inches from the center of the bullseye, or in other words, the string measure of the shots could not exceed fifty inches.  This result had to be verified by a county official, and the results were then sent in for approval (Marcot 2007 p.35).

A newspaper article of the time confirms the standard for Berdan sharpshooter applicants: “…that no man is admitted who does not shoot, at 600 feet distance, ten consecutive shots at an average of five inches from the bull's-eye. That is, the aggregate distance of the whole ten shots must not exceed fifty inches.”  (Harpers Weekly 1861).  This was remarkable for a time when little actual marksmanship practice was conducted by most infantry troops; in fact, some authorities claim that as many as one quarter of the enlistees in the Federal Army had never fired a rifle before their first battle, and never engaged in formal target practice outside of battle.

While most infantry manuals of the Civil War make no mention of target practice, some cavalry manuals (e.g., Cooke’s Cavalry Tactics) do.  In Cooke’s instructions, troopers were to ride past a target at various ranges, starting at ten paces (for recruits) and working up to one hundred, and at various gaits from a walk through to a gallop.  No time limits are mentioned for the evolution, nor does he provide any minimum standards of accuracy, however Cooke provided an exemplar form to use for recording each trooper’s results which included a place for indicating the string test measure (Cooke 1864 pp. 98-100).

The most explicit source we have for the string test comes from a book by Henry Heth on marksmanship dating from 1862 (p 61); note the similarity to the Berdan qualification:

2d. The target will be a circular board or boards three feet in diameter. The middle of the target will be marked by the centre of a black circle eight inches in diameter. The rest of the target will be painted white.
3d. Each man fires ten balls. The distance fired from will be 200 yards.
4th. After each shot, the distance from the centre of the ball-hole to the centre of the target will be measured and recorded.
5th. Balls which strike by ricochet will be counted as having missed the target.
6th. Each miss counts 20 inches on a man's string. In all cases the man whose string is shortest is selected.

The method continued in use even after the War.  In the Report of the Chief of Ordnance to the Secretary of War published in 1884, it was reported that General Ord, then in command of the Department of California, directed target practice to be held at each post once a week, and saying that "he specified that the value of the shot should be determined by string measurement, i.e., by measuring from the center of  each hit made by a marksman to the center of the bull's eye; these distances added together and divided  by the number of shots fired by the man gave the value to the string" (Ordnance Dept. 1884 p. 95).

Procedure
To determine the string test measurement, hold the end of a string at the bullseye and pull the string to any of the bullet holes.  Pinching the string at the point where it reached the hole, move that part back to the bullseye, and stretch the string to another bullet hole, pinching the string again at that new point.  Repeat this until the distance from the center has been measured to each of the hits.  The total length of string determines the final score, or you can divide the string length by the number of rounds to give an average score per round.  Any misses should be assigned a standard figure, as in Heth’s standard of twenty inches, however, it makes sense to vary that measure according to the range at which you are shooting.

The string test can be used to determine an individual score as described here, or it could be used to determine a qualifying score, as in the Berdan test discussed above, but the historical shooter will probably find the individual score to be the most useful when judging his own performance.  The average measure per round is most useful for tracking one's results over time, or for comparing different kinds of shooting, such as when using different powder loads, or at different ranges, or when comparing different bullet types.  For simplicity, I use a flexible tape measure for measuring the results, however, for more historical verisimilitude a simple piece of string can be used and then measured afterward.

Using a tape to measure the distance to each bullet hole.

An example of the string test measurement for a hypothetical target.

An example of a string test result:  11 rounds fired from a Remington New Model Army revolver at 15 yards resulting in a string of 43.5 inches, or 3.9 in./round.

Works Cited
Anon. “Colonel Berdan and his Sharpshooters.” Harper's Weekly. 24 August 1861.(https://www.2ndusss.com/research-library/harpers-weekly-august-24-1861) 

Cooke, Philip St. George. Cavalry Tactics: or Regulations for the Instruction, Formations, and Movements of the Cavalry of the Army and Volunteers of the United States. New York: J. W. Fortune, 1864. 

Heth, Henry.  A System of Target Practice for the Use of Troops When Armed with the Musket, Rifle-musket, Rifle, or Carbine.  New York: D.’ Van Nostrand, 1862. 

Marcot, Roy M. U.S. Sharpshooters: Berdan’s Civil War Elite. Mechanicsburg, PA: Stackpole Books, 2007.

United States Ordnance Department.  Report of the Chief of Ordnance to the Secretary of War for 1883, Washington: Government Printing Office, 1884.