384 
PROPOSED RUSSIAN FIELD GUN. 
length of bore was 21 calibres. The weight and length of the piece 
were thus laid down with the intention—1st, of diminishing as far as might 
be the strain on the carriage, and 2nd, of utilising as far as possible 
the action of the heavy charge on the projectile. With the above data 
and a pitch of rifling of 1 turn in 60 calibres, a velocity of 1340 ft. per 
second was attained. The following are the results of the experiments:— 
Distance. 
Angle of 
elevation. 
Angle of 
incidence. 
Mean quadratic 
deviation. 
Vertical. 
Lateral. 
sagenes. 
yds. 
o / 
O / 
yds. 
yds. 
500 
1167 ' 
2 25 
2 45 
0-66 
0-93 
1000 
2333 
5 40 
7 8 
2-54 
2-40 
1500 
3500 
9 55 
13 57 
10-43 
4-27 
Comparing these results with the analogous data of the Russian 
service field guns, we see that a great increase in accuracy and in 
flatness of trajectory was obtained. 
With the service 4-pr. and 9-pr., which fire with a gun-charge of 
one-ninth of the weight of the projectile, giving an initial velocity of 
1004 and 1060 ft. per second respectively, the following are the results 
of practice:— 
Gun. 
Distance. 
Angle of 
elevation. 
Angle of 
incidence. 
Mean quadratic 
deviation. 
Vertical. 
Lateral. 
sagenes. 
yds. 
O / 
O 
/ 
yds. 
yds. 
r 
50Q 
1167 
3 20 
3 
48 
1-40 
1-03 
4-pr . 
| 
1000 
2333 
7 39 
9 
45 
5-44 
3-31 
l 
1500 
3500 
12 32 
18 
59 
22-44 
6-93 
r 
500 
1167 
2 57 
3 
24 
1-03 
0-86 
9-pr . 4 
1000 
2333 
6 52 
8 
26 
4-20 
2-36 
1 
i 
1500 
3500 
11 43 
15 
36 
13-15 
4-90 
Determining from these data* the probability of a direct hit on a 
vertical target 6 ft. high by a length of 25 paces (58 ft.) we find :— 
* To compare the accuracy of fire, we do not take the mean quadratic deviations in length, as 
they principally depend on the angle of incidence; but seek the vertical deviations, which, though 
dependent on the inclination of the trajectory to the horizon, are much less affected by the angle 
of descent than the longitudinal deviations, in consequence of the great tension of the trajectory. 
In the case where it is intended to compare the results of high-angle fire, we should compare the 
longitudinal deviations with each other, and not those obtainable on a vertical target.— Author's 
note . 
