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MINUTES OF PROCEEDINGS OF 
strong and heavy, will be unwieldy; and that with the same weight of 
metal, the breech-loading is a weaker and less enduring construction than 
the muzzle-loading. 
On the other hand, a muzzle-loading gun has a simpler and stronger 
construction, but the gun detachment are more exposed than with a breech¬ 
loading gun, and if loaded carelessly, the shot may not be rammed home , in 
which case the metal of the gun may be fractured by the suddenly 
condensed gas. 
Systems of Rifling. 
I will now say a few words on the different systems of rifling. In what 
does a system of rifling consist ? Essentially in the method of giving the 
rotatory motion to the projectile. This definition will not satisfy some 
inventors, who wish to claim a particular twist as a part of their system of 
rifling . It would, however, be quite as reasonable to claim a particular 
charge. The rotatory motion, as you all know, is given to prevent the 
projectile from turning over in flight; and the velocity of rotation required 
depends upon the form, length, and weight of the projectile, no matter what 
the system of rifling may be; in fact, the number of revolutions made by a 
I. Y. 1 
shot = j— and therefore, with the same charge, the same twist 
must be obviously necessary.* 
A twist, like a charge, may suit a particular rifled gun, but this is quite 
another thing. A gaining twist is advantageous, for, by employing it, the 
initial, strain upon the gun is reduced, the rotatory motion not being given 
when the shot is set in motion, but gradually acquired as it moves down 
the bore. It is better to give rather more twist than is required under 
ordinary circumstances at the expense of a little extra strain; for should the 
twist be merely sufficient to impart the necessary rotatory motion with the 
service charge, the velocity of rotation will probably be too low with a 
reduced charge to keep the projectile steady in flight.t 
The diameter of the bore has also been often mixed up with the system of 
rifling, with which it can have nothing whatever to do. As the diameter is 
decreased, so will an elongated projectile oppose a less surface (in proportion 
to its weight) to the resistance of the air, or of that of the substance fired 
at; but, on the other hand, it will expose a less area to the force of the gas, 
and will, therefore, have a lower initial velocity; it will have less capacity as 
a shell; its cartridge must be elongated, thereby throwing the strain forward, 
the amount of powder that can be usefully employed will be less, and if the 
length of the bore be not increased, the expansion of the gas will be more 
limited. This question has been discussed in this room, and should be now 
thoroughly understood. In the table, p. 221, the loss of initial velocity by 
decrease in the size of the bore is clearly shown :— 
* The I. V. is very little affected by the system of rifling. 
f This was practically shewn by the inaccurate practice of the 600-pr., when fired with a 
small charge. 
