THE ROYAL ARTILLERY INSTITUTION. 
409 
The length of bore is 20 calibres. 
Calibre . 12*608 ins. 
Projectile .... 770lbs. 
Weight of gun.. 40 tons. 
Charge ...... 132 lbs. cubic powder. 
Muzzle velocity .. 1382 f.s. 
The gun has not yet been subjected to a trial similar to that 
described in the case of the 15-ton gun; but the quality of the 
metal is so exceedingly good, and the success of the Turin Grun 
Factory so uniform, that no sinister result is anticipated. 
The gun will be subjected to searching proofs this spring at 
Santa Maurizio—the Shoeburyness of Italy. 
The shell employed with the larger ordnance merit attention, 
especially as ensuring stability and preventing windage. They 
are of cast-iron, with ogival head, and are provided with four 
or five rings of copper, running round the circumference of the 
shell. These copper belts are hammered by hand into undercut 
grooves cast in the body of the shell. 
The outer surfaces of these rings are cut into four grooves 
running round the shell, in order to allow, when fired, the surplus 
copper to be squeezed into them, and avoid “ stripping.” 
Copper has been adopted instead of lead, in spite of its greater 
expense, consequent on the results of experiments made with 
projectiles fitted with copper rings and lead coats respectively. 
The following table is compiled from an experiment at Santa 
Maurizio, with ten projectiles of each description, fired with 
equal charges, and from the same gun; range about 2000 yds. 
The result speaks for itself:— 
Lead. 
Copper. 
•570 
•327 
*39 
•78 
•77 
•184 
•248 
1-90 
•350 
•205 
Mean deviation | y ertica j . 
“ Accuracy ” of fire deduced from Didion’s 
formula ... 
Radius of circle con-1 -i 
taining half the total > . f 1 
number of hits .J Actttal 
Captain Biancardi showed me a working model of a new 
muzzle-pivoting gun and carriage of his own invention, which 
by its simplicity and completeness bids fair to eclipse all its 
predecessors. The Italian Government have decided on giving it 
a trial with the new 40-ton gun; but until the experiment takes 
place, no detail is allowed to be given. Full details have, however, 
been promised, as soon as the trial is completed, which is expected 
to take place next month. 
The working of the wrought-iron sliding carriage appeared 
very simple and satisfactory. It is fitted with a double hydraulic 
buffer, much simpler and lighter than the single one in use in the 
50 
Dimensions. 
40-ton gun tested 
at Santa Mau- 
rizjo. 
Projectile for 
heavy ordnance. 
Four or five rings 
of copper. 
Why copper em¬ 
ployed instead of 
Experiment at 
Santa Maurizio. 
New muzzle- 
pivoting system. 
To be kept secret 
till tried. 
Wrought-iron 
sliding carriage, 
Double buffer. 
