5 
PRECIS 
1ND 
TRANSLATION. 
“MEMORIAL _DE ARTILLERIA.” 
AN IMPROVED DRIVING-BAND EOR B.L. PROJECTILES. 
TBAN8LATED BY 
MAJOR S A M U T , A.O.D. 
Tiie life of a gun, like that of man, is threatened by diseases which tend to bring 
it to an untimely end. Whilst medical science is daily bestowing its attention to 
arrive at and extirpate the source of disease in man, the problem of preserving guns 
from decay cannot but prove of vital interest to every gunner, knowing how much 
depends on a thorough good condition of our armaments and at what cost to the 
country they are produced and maintained. Erosion may be said to be to a gun 
what consumption is to the human body and any suggestion which may lead to 
minimize its deadly effects cannot but be hailed with satisfaction. We are there¬ 
fore pleased to record the considerations of Captain Sarmiento of the Spanish 
artillery on the causes which produce erosion in guns and liis ingenious method 
for ensuring a perfect obturation between the projectile and the bore of B.L. 
guns. 
It frequently happens that guns which have only fired a small number of rounds 
are rendered unserviceable through deep erosion and cavities in that part of the 
bore comprised between the beginning of the rifling and the point in which the 
pressure reaches its maximum intensity. 
The principal cause of this is, in our opinion, due to insufficient obturation 
afforded by the driving-bands now in use. It is true that their diameter is larger 
than that of the bore across the grooves, but this is not enough to stop the rush of 
gas, produced by the combustion of the charge, between the driving-band and the 
rifling. 
It is, in fact, evident that, during the period in which the gas is acting on the 
base of the projectile, the former tends to make for the muzzle by endeavouring 
to escape between the sides of the bore and the driving-band on the projectile, 
and if the two latter be not perfectly concentric, it will doubtless attain its object 
producing along the unsealed grooves small furrows which will subsequently 
extend with amazing rapidity and end by rendering the gun unserviceable. 
Another consideration of great importance and which demonstrates the in¬ 
sufficiency of obturation furnished by the present driving-band is:—That on being 
O, VOL. XXIV, 
