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|S_ | __| |__ __|
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| Section. 
H /
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| W |
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Besides these objections to this target, another and more serious one is the irregularity in the manner of breaking the circuit.  It has been proved that times required for a flat headed and an ogival headed projectile to rupture the current are very different.

To remedy these defects a new and very ingenious target has been devised and used with great success at the United States Military Academy at West Point.  The top of the target is a wooden strip, F, on the upper side of which are screwed strips of copper, A A, about 1/2 in. wide, and 1/8 in. thick.  The connection between two adjoining strips is made by a copper cartridge, C, which is dropped in a hole in the frame bored to receive it.  This cartridge is the one used in the Springfield rifle.  Inside the cartridge is a spiral spring, S, which, acting on the bottom of the hole and the head of the cartridge, tends to make the latter spring up, and so break the circuit.

To the hook, H, which is attached to the cartridge, is suspended, by means of a string, the lead weight, W, thus drawing down the cartridge and making the circuit between A and A’.  All the weights being suspended the current comes in through the post, P, passes along the copper strips and out of the corresponding post on the other end.

On firing the projectile cuts a string, and the spring at once causes the cartridge to spring up, thus breaking the circuit.

It is not possible for the projectile to squeeze between the strings and not break the current, for in so doing the cartridge is tipped slightly, which is sufficient, as it breaks the current on one side.

This target is used in connection with the Boulenge chronograph.  Two targets are established at a known distance apart, say 50 ft., and the time required for the projectile to pass over this distance is determined by finding the difference in the time of cutting of the two targets, by finding the difference in the time of falling of the two rods, caused by the demagnetization of two electromagnets in the same circuit with the targets.

By means of a disjunctor both rods are dropped at the same time, the shorter one releasing a knife blade which makes a cut on the longer one.  Now both rods are hung from the magnets again and the gun is fired.

The projectile passes through the first target, breaks the circuit, demagnetizes the magnet of the longer rod, and it begins to fall.  On passing through the second target, the projectile causes the shorter rod to fall.  This releases the knife blade, and a second cut is made.  The time corresponding to the distance between these cuts is the time the longer rod was falling before the second rod began to fall or the time between the cutting of the two targets by the projectile.