210 
MINUTES OF PEOCEEDINGS OF 
projectile, or a line parallel to it, an angle equal to the angle of rifling at the 
muzzle, viz.: 1 turn in 45 calibres, while the line BB , touching the other 
sides of the studs, makes with the same line an angle equal to the angle of 
rifling at the breech, viz. 0. 
The difference in the size of the studs, therefore, depends on the pitch of 
the rifling, and the distance they are apart, and this again on the length of 
the projectile. 
When the shot enters the gun, the front stud touches the side of the 
groove on the bearing or driving side, but as it goes down, it gradually 
approaches, and when home, bears against the opposite side of the groove. 
Theoretically, on firing, the front stud would not touch the groove on the 
bearing side until the projectile reached the muzzle of the gun, the back 
one sustaining all the friction consequent upon rotation, but, practically, 
this friction is so great that the bearing side of the back stud is considerably 
worn away, and the front one comes to bearing before it otherwise would, so 
that the projectile leaves the gun steadied by two bearings. 
Different hinds of projectiles . 
There is at present only one sort of projectile actually approved for the 
7-in. and 9-in. guns, viz. common shell; but some of the following will 
probably be introduced, if not all, viz. chilled shot and shell, cast-iron double 
shells, Colonel Boxer's shrapnel shell for rifled ordnance, and Lieutenant 
Beeve's case shot. 
Common shell . 
The common shell is cylindro-conoidal in shape, about three calibres in 
length, fitted with rows of studs as described, and lacquered inside to prevent 
excessive friction, and consequent premature explosion, of the bursting charge, 
from the rotation during flight. The fuze hole is fitted with what is called 
the B bush, which is conical inside, like the fuze holes of common smooth 
bore shells, but larger. (A few were issued at first bushed to the Moorsom 
gauge).* The P bush receives Pettman's new general service percussion 
fuze, and Colonel Boxer's new wood time fuze for M.L. ordnance. The fuze 
hole is countersunk *1 inch. 
These shells have two holes in the head for the claws of the extractor to 
catch in. 
The 7-in. shell weighs, empty, 106 lbs. 12 oz., filled, 115 lbs. 2 oz. 
The 9-in. u « « 232 lbs. « 250 lbs. 
The 7-Pr. M.L. Cun for Mountain Service . 
Three guns of this calibre have been made— 
Bronze 3-prs., rifled, of 229 lbs. 
Steel guns « 191 „ 
n n 155 n 
* These bushes are to be taken out, and the shells re-bushed with the F bush. 
