| | |
3,000 lbs.| 9 | do. | do. | 10 |
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The cannon-powder for proof shall be of not less than 1,500 feet
initial velocity, as determined by the gun-pendulum at the Ordnance
Yard, Washington.

It shall be filled in service cylinders, and well settled.

For chambered pieces the increased charges should fill the chamber and
necessary portion of the bore.

The projectiles shall be of full weight, and not below the mean gauge;
the shells shall be filled with a mixture of sand and ashes, to bring
them up to the proper weight of the filled shell.

Sabots for the shell and a gromet wad over the shot.

The gun should be fired on skids or a proving-carriage, to test the
trunnions.

If five per cent. out of any lot offered for ordinary proof under a
contract shall fail to sustain it, the whole may be rejected, as may
be stipulated in the contract.

WATER-PROOF.

32. The pressure to be applied in the water-proof will be two
atmospheres, or thirty pounds to the square inch.

The penetration of water in this proof through the metal of the piece,
in any place, will cause the rejection of the gun; and if, on
examination after the water-proof, there shall be any defects
indicated by weeping or dampness in the bore, the gun shall be
rejected.

The water-proof is alone to be depended on to detect minute clusters
of cavities in the bore, which for this purpose should be perfectly
dry, and examined by sunlight. All inspections, consequently, should
take place in fair weather, and when the temperature is above the
freezing-point.

MARKING GUNS.

33. Guns for the naval service, received by authority of the Bureau of
Ordnance, are to be marked in the following manner, viz.:

On the cylinder, in the line of sight near the sight-mass, all
accepted guns are to have stamped an anchor two inches long.

Drawings of these stamps will be furnished by the Bureau of Ordnance.

On the base ring or line, the initials of the foundry, the register
number, and the weight of gun in pounds.

On the right trunnion, the calibre and year of fabrication.

On the left trunnion, the letter P. and the initials of the inspecting
officer; all the above in one-inch letters.

On the upper jaw of the cascabel, the preponderance in pounds to be
stamped lightly with half-inch figures.

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