...Railway artillery - Personal Page of GENE SLOVER

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disadvantages are the fact that it adds only fractionally to the life of
tho gun, that it is inapplicable to short pieces, and that it requires a
spodal powder charge for such guns as are repaired by it.
615. Reboring consists of turning out the entire interior of the bore
to a large diameter and rerifting. This necessitates the use of a different
caliber of ammunition, and of a lower powder pressure and
muzzle velocity, reducing the range, in some cases, materially. The
life should be almost as many rounds at the new caliber as at the old.
The advantages of this method are that no forging equipment or
shrinking arrangements are necessary, and that the life of the gun
is doubled. The disadvantages are the reduction in range and the
necessity for using a different caliber of ammunition.
616. Relining consists of turning out the interior of the bore to a
larger diameter and inserting a liner, in which the rifling of the original
caliber is cut. This liner is usually inserted by shrinking the gun
over it, but the method of autofrettage or expanding the liner into. the
gun by hydraulic pressure is also being developed. This method is
probably inapplicable to small calibers on account of the thinness of
the liner that would have to be used. The advantages of this method
are that it requires a fairly light forging and that it gives a gun pra.c- •
tic ally as good as new and using the same ammunition as the old one.
The disadvantages are the forging facilities required, the length of the
process, estimated as nearly 900 hours on the United States 12-inch
gun, and the fact that there is considerable doubt about the possibility
of rechambering relined guns.
617. Retubing consists of disassembling the gun and building it up
again around a new tube, just as it was built up at first. This, of
course, gives a gun in every way as good as new. The disadvantages
are, of course, the great amount of forging and shrinking equipment
required, and the length of the process. .
618. MOUNTs.-Wear and tear on railway mounts are of the same
character a" take place on railway rolling stock and 'seacoast gun
carriages. Breakages and derangements are of a purely mechanical
character, and generally of fairly minor magnitude. Repairs require,
principally, a well-equipped machine shop, and no detailed discussion
of them is called for.
619. ORGANIZATION AND ARRANGEMENTS FOR MAINTENANcE.-In
the British Army the maintenance shops for railway artillery were
under the command of the ordnance officer at the base at Calais. In
the French Army they were under the chief inspector of artillery, for
fairly light repairs. Major repairs were made at the works of the
Schneider and other private corporations. In the American Army
the exact arrangement was never finally fixed, but to all intents and
purposes, the repair shops for railway artillery were under the commanding
general of the railway artillery reserve. It is felt, as a
r1'9111t of observat.ions of the workings of these various sYStems. that
Digitized by Coogle