388 
PEOPOSED EUSSIAN PIELD GUN. 
its liquid state; further, after the gun has been bored to a calibre 
slightly below the finished dimensions, to drift it with wedges slightly 
larger than the then diameter—thus subjecting it to internal pressure ; 
and finally to bore up and rifle the gun. A few heavy 4-prs. of this 
pattern have been made—some with a regular twist of different pitches 
(from 1 turn in 50 to 1 turn in 60 calibres), others with an increasing 
twist. 
Rifling with a progressive twist presents the advantage of giving a 
small inclination to the grooves, with reference to the axis of the piece, 
in that part of the gun where the pressure of the gas is at its greatest; 
so that the driving sides of the grooves incur little danger of injury. 
As the projectile, however, approaches the muzzle, the inclination of 
the grooves increases with the velocity of translation; and thus, 
without danger to the driving sides of the grooves, it appears possible 
to attain a considerable velocity of rotation, and thereby to increase the 
precision of fire. 
In the experimental 4-pr. gun, the inclination of the increasing twist 
of rifling at the muzzle corresponds to a pitch of 1 turn in 45 calibres. 
Ths projectiles for this piece have a thicker base to the common shell 
than the service shells, to avoid the danger of a burst in the bore. 
Some of the common shells for the guns rifled with a regular twist are 
coated with a hard alloy, and others have rings of copper wire- {sic)-. 
The part of the shell intended to take the rifling is of an alloy harder 
than lead, to prevent stripping and irregularity of motion in the bore. 
By this means increased precision of fire is aimed at. With the gun 
rifled with an increasing twist, it is intended to use projectiles with 
copper rings 1 One of the latter is—as may be seen in the drawing— 
near the base of the projectile, and takes the grooves in firing. At the 
point of junction of the ogive and cylinder of the shell is a second ring, 
of a diameter somewhat less than that between the lands of the gun. 
This ring is intended to steady the shell in the bore. 
Besides the ordinary common shells with solid walls, it is intended 
to try double-walled shells. In these shells—as may be seen in the 
drawing—the walls are formed of two concentric strata, each of which 
is formed into, a series of pyramids with blunt apices.* 
This method of construction is intended to increase the number and 
uniformity of the fragments in bursting. If it be found that these 
shells are not inferior to ordinary shells in their effect against masonry, 
it would be advisable to adopt them in supersession of the old pattern. 
The heavy bronze 4-pr. is intended for the armament of the field 
batteries, which however would partially retain the present 9-pr. 
The horse artillery would still be armed with the present 4-pr. gun of 
20 pud (6 # 45 cwts.) ; an extremely light piece—light beyond com¬ 
parison with the heavy 4-pr.—and exactly realising the main essentials 
of a gun intended to accompany cavalry. 
Let us now compare the service field guns of foreign powers with 
the Russian artillery, inclusive of the new gun. In two of the following 
tables will be found numerical data regarding the construction of the 
guns and projectiles, while the third will give some idea of their effect:— 
* As seen in a longitudinal section. Each pyramid is a triangle.— ■'Eng. Tr. 
