THE ROYAL ARTILLERY INSTITUTION. 
67 
(2) " A steel smooth-bored gun of 8*58 inches (E) which was intended to 
afford complete proof of the strength of Krupp's steel, guns, by its resistance 
to a great number of rounds fired with spherical bullets and a large charge. 
(3) “ A smooth-bored gun of 11*06 inches in an 8*58 inch block bored up 
(E) for trial with spherical shot and a large charge. This last experiment 
was to be the pierre de touche both as regards the endurance of the gun, and 
the action of spherical projectiles of large calibre on iron plates. 
11. “ The 8*58 inch gun a rayures par alleles or shunt rifled, was fired at 
the iron target at a distance of 1167 yards. It appeared that plates of 4*7 
inches were penetrated not only with a charge of 33 lbs. of pellet powder, 
but also with the charge reduced to 27| lbs. 
" The fire of this gun and of the gun with Trench rifling with the 
larger charge (33 lbs.), was in consequence restricted to 46 rounds; and 
was then continued with the charge of 27 \ lbs; 169 rounds with this charge 
were fired with the former and 240 with the latter. A slight wear of the 
metal was perceptible in both guns at the seat of the shot, proceeding from 
the action of the gas in its escape by the windage. This wear is due 
probably and principally to the mechanical action of the gas. It was more 
considerable in the second gun than in the first, and was no doubt caused by 
the greater number of rounds fired. This novel fact, confirmed by experi¬ 
ment, and to which little attention has heretofore been given, is of great 
importance in relation to the question of steel rifled guns of large calibre. 
12. " This fact proves that muzzle-loading guns of large calibre in which 
the gas is allowed to escape by windage, and which fire heavy projectiles with 
large charges, even when made of steel of absolutely the best quality (and no 
one will question that to this category belong the guns of M. Krupp) are 
subject necessarily to a wearing action, and that the service of the gun 
cannot be rated higher than 250 rounds without danger of the projectiles 
producing such injuries in the bore as might endanger it.* 
13. "The experiment made by order of the Minister of Marine with the 
steel gun ( E ) of 8*58 inches, in which spherical balls were fired with a charge 
of 27*5 lbs. of common powder, have given proof of the great resistance of 
Krupp’s steel guns, and have confirmed the fact already stated. The gun 
stood 1025 rounds, but the escape of gas by the windage produced a con¬ 
siderable wear on the surface of the bore at the seat of the shot. A similar 
result followed the trial of the other smooth-bored gun (F). This piece, 
bored up to 1T0 inches from the calibre of 8*58 inches, stood 790 rounds, 
firing spherical shot of 198 lbs. with a charge of 44 lbs. of pellet powder, 
after which it was observed that wear of the metal was taking place at the 
seat of the shot. The wear was however but trifling, so that the piece 
remained serviceable. With respect to the comparatively small wear of this 
piece as compared with that of the gun of 8*58 inches {E) tried by the 
* The French translation has it “ de crainte que si Von continuait le tir, les projectiles ne 
jproduisissent une obturation dans Vame dn canon.” 
