THE 80-TON GUN. 
4(33 
THE 80-TON GUN. 
BY 
MAJOE E. MAITLAND, E.A., 
ASSISTANT SUPERINTENDENT ROYAE GUN EAOTORIES. 
The early history of this remarkable weapon formed the subject of a 
paper contributed by the present writer to these “ Proceedings ” last 
January. The causes which led to the designing of the gun; the 
object sought to be obtained by it; the progress of its manufacture; 
its proof; and the first series of experimental rounds fired from it by 
the Committee on Explosives, were therein described. It was shown 
that the results obtained somewhat exceeded anticipation ; and while 
it had been hoped that the penetrating power would reach the point 
sought for in the final stage, there was now a possibility that the gun 
would do the work assigned to it, even in the sub-calibre of 14*5 ins., 
to which it was at first bored. 
It was stated that the highest admissible result then obtained was 
yielded by a charge of 230 lb. of powder in cubes of 1'7-in. edge, 
which propelled a shot weighing 1260 lb. with a velocity of 1543 f.s. 
The useful work, or “ energy,” produced by the explosion reached 
20,780 ft. tons, while the mean pressure in the powder-chamber did 
not exceed the limit laid down by the Committee; though it should be 
remarked that an undesirable pressure was recorded at A. From this 
result, then, it appeared at least possible that the gun, even in its 
14'5-in. calibre, would perform its task—viz., the piercing of 20 ins. of 
iron armour, strongly backed, at a range of 1000 yds.; and it was 
expected that the further development of its powers would place the 
question beyond doubt. 
The bore sustained the trials without any perceptible injury or 
change; and the paper alluded to carried the history up to the point 
where the gun was placed in the boring machine, that its calibre might 
be enlarged to 15 ins.—the intention at the time being to proceed by 
half-inch stages to a final diameter of 16 ins. 
I have now to give an account of the progress of the experiments 
since made. On the completion of the boring up of the gun to 15 ins., 
it was again mounted on its travelling firing carriage and taken to the 
Proof Butt. Shot of the weights previously fired were provided, and 
a sufficient quantity of each size of powder used in the former trials 
was preserved, so that the results should be directly comparable. 
