486 
ARMOUR-PIERCING- PROJECTILES. 
w 
Table showing the Value of ^ for Palliser shells in Service. 
Gun. 
Approximate 
w 
If TF=-41# 
value of W. d. 
^ ’ the weights wouli 
lbs. 
ins. 
lbs. 
12-5-in. 
.... 800 ... 
12-425 
... *4171 
... 788-26 
12-0 ,, (35-tons) 
... 700 ... 
11-925 
... -4128 
... 695-18 
12-0 „ (25-tons) 
... 600 ... 
11-920 
... -3543 
... 694-41 
11-0 „ . 
.... 580 ... 
10-925 
... -4065 
... 534-62 
100 a . 
.... 400 ... 
9-920 
... -4098 
... 400-24 
9-0 „ . 
.... 250 ... 
8-920 
... -3523 
... 290-99 
8-0 „ . 
.... 180 ... 
7-920 
... -3623 
... 203-69 
7-0 „ . 
.... 115 ... 
6-920 
... *3470 
... 135*86 
Perhaps the best shell would be one which could combine a fairly 
flat trajectory with a striking velocity of 1000 f.s. at about 2500 yds. 
range, being made as long as the twist of the rifling would allow it to 
be, so as to be able to carry as large a gun-cotton bursting charge as 
possible, due regard being had to the proper strength of the walls 
and head to which the amount of cavity for the bursting charge must 
always be subordinate. The projectile must, of course, not be so 
heavy as to strain the gun unduly, but this is easily avoided by the 
use of slow burning powder and proper air-spacing. 
The Committee wished to have further experiments made to deter¬ 
mine the best value for a. 
It was found that when firing obliquely at wrought-iron that, if the 
angle made by the line of fire to the normal to the plate was 37° 4', 
and the plate was beyond the power of the gun to perforate, only 
scoops were made on the face. When the angle was reduced to about 
30°, all the natures of shell tried bit the plate. Some scoops were 
made, but it was thought that these were probably due to deformation 
on impact. Possibly they were due to the helical motion of the projec¬ 
tile at short ranges. 
When the plate was below the power of the gun the projectiles bit 
at a greater angle. A plate 8*7 ins. thick was almost perforated at an 
angle of 35° and 36° 30', but at an angle of 40° a scoop was 
produced. 
The Committee believed that thinner plates could be perforated at 
much higher angles, and this belief is borne out by the results of the 
Nordenfelt and Hotchkiss trials. 
With steel-faced plates beyond the power of the gun only scoops 
were made with angles of obliquity of from 25° to 27°. 
When the plates were below the power of the gun the steel-face 
ceased to deflect the projectiles. A plate of 3J ins. steel welded to 
5J ins. iron was perforated at angles of 20° and 25°. 
It was considered on the whole that a good 9 or 10-inch compound 
plate was about equal to a good 12-in. iron plate for resisting a single 
blow, but that it was decidedly inferior when repeated blows were 
given, 
