THE ROYAL ARTILLERY INSTITUTION. 
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Effect of shot varying in weight and velocity , hut with equal vis viva. 
The object of this experiment was to ascertain the difference of effect 
between cast-iron shot from 68-prs. and 110-prs., striking iron plates at such 
velocities as would make W v 2 equal in each case. 
Eor this purpose the following were used :— 
The 68-pr. threw a 66-lb. shot, with a charge of 16 lbs. of powder, at a 
velocity, at 200 yards, of 1367 ft. 
The 110-pr. threw a shot of 110| lbs., with a charge of 11| lbs., at a 
velocity of 1056 ft., and the same gun threw a shot of 200 lbs., with a charge 
of 11 lbs., at a velocity of 786 ft. 
The plates fired at were 3-in., 3J-in., 4J-in., and 5J-in. 
It was difficult to mark the general result of this experiment, but the 
deepest indent was decidedly made by the 68-pr., and the least indent by 
the 200-lb. shot; all the shot of course broke up, and, but for the difference 
of work thus consumed, there is little room to doubt that the total effect 
produced upon the plates would have been equal for all three shot, local and 
clearly marked with the lighter shot and higher velocity, more general and 
less defined with the other shot, but, as is stated above, the result was 
somewhat obscure. 
Armstrong shot of various weights against iron plates. Nov. 14, 1862. 
The 110-pr. Armstrong gun was made to fire on this occasion lighter shot 
than its proper projectiles at higher velocities, and, of course, with increased 
charges of powder. The range was 200 yards, and the plates were 4J in. 
and 5 in. thick. 
The comparison made was between the service 68-pr., throwing spherical 
cast-iron shot at a velocity of 1367 ft., and an Armstrong 110-pr. throwing 
cylindrical cast-iron shot varying from 60 lbs. to 68 lbs., at velocities ranging 
between 1580 and 1475 ft. 
The result of this was that the indent made by the 68-pr. service gun was 
2 in. deep, and that by the Armstrong gun from 2J to 3 in. deep, and the 
damage altogether appeared to be in the same proportion, which corresponds 
pretty nearly with the relative values of W v 2 in the different shot. 
Whitworth and Armstrong 12 lb. steel shot. Nov. 1862. 
This comparative trial was made with 12-pr. breech-loading rifle guns, 
against a target covered with 4|-in. armour, at 100 yards. The shot were 
of steel, charge of powder, 2 lbs. One of the Armstrong round-headed shot 
made an indent rather more than 2 in. deep, and a flat-headed one made an 
indent of 1 in.; the former was slightly broken, the latter only set up. 
The Whitworth made an indent of 1*4 in. and broke up. 
Projectiles of various forms and qualities of metal. Dec. 1862. 
At this time several cast-steel shot, and shot made of other patented 
materials, were tried, with a view to determine the best form and material 
for projectiles intended to penetrate iron plates. 
