Maintenance of Guns and Mountings

The following text has been scanned from OU5205 Instructions for Ordnance Artificers for the Use of His Majesty's Fleet, 1921, produced by the Gunnery Branch of the British Admiralty (it is Chapter XII, beginning on page 149).


Bright Parts of guns.

All outside parts of ordnance which are supplied bright, including breech mechanisms, are to be kept clean by the use of oil only, except in cases where the gun is not required to be used for some time, when they are to be coated with a mixture of white lead and tallow.

Brick not to be used.

With the exception of the breech and other working parts, the outside of guns should be red-leaded and painted. No part of a gun other than the face is to be burnished or polished with any gritty substance such as emery paper or "brickdust." Those parts which are bare are to be kept oiled. Great care is to be taken that the surfaces of clinometer planes and sight brackets are uninjured; oil only should be used for cleaning then and the steel parts of breech mechanism and sights. "Brick" should on no account be used for cleaning a working part of any kind.

Preserving Screws.

All preserving screws should occasionally be removed and oiled.


Bores of Guns.

On board ships in commission, bores of guns are to be kept cleaned and oiled. As soon as possible after firing, the bores and chambers of the guns are to be properly cleaned and well oiled. Particular care is necessary for the upper parts of the bore.

Oil removed before Firing.

All superfluous oil and grease are to be removed from the bores of guns before firing, as those substances tend to reduce appreciably the muzzle velocity for the first round.

As the result of experiments following on the breaking up of lyddite shell in a 4 in. and a 12 pdr. gun, it has been demonstrated that the accidents were probably due to heavy lubrication of the bore for a short distance from the muzzle.

Care is, therefore, to be taken that an excess of oil or vaseline is not left in the bores of guns.

The bores of guns which have been filled with lubricant for preservation are to be thoroughly cleaned before firing.

After firing Cordite.

After firing with cordite, the bore will be thoroughly washed out; and, when dry, lightly coated with mineral jelly.

Special piasaba cleaners are supplied for 4 in. guns and above.

After using Aiming Rifles.

After an aiming rifle has been used in a gun, the bore of the latter will, as soon as possible after the aiming rifle practice, and before Service ammunition is fired from the gun, be thoroughly cleaned, so as to remove any residue which may have formed therein.

Such residue will usually be found in a. broad ring round the bore of the gun in front of the position of the muzzle of the aiming rifle when the latter is in place; and if left for any considerable time may become exceedingly hard and difficult to remove. It is in fact quite enough to cause the premature explosion of a shell in the gun.

6 and 3 pdr. Q.F. Guns.

In the case of 6 and 3 pdr. Q.F. guns, the fittings should be thoroughly cleaned after firing by dismounting the mechanism and washing each part with warm fresh-water soapsuds. When thoroughly dry the parts should be oiled.


Nothing is to be kept in the bores of guns when unloaded, except the tampeon.

Extemporised tampeons made on board are not to be used. In certain cases 6 and 3 pdr. guns have been rendered unserviceable by rusting of the bores at the first six inches from the muzzle. This is attributable to the use of these tampeons, which, being usually covered with fearnought, absorb moisture and thus cause the bores to corrode.

Guns used for saluting.

Care is to be taken that guns used for saluting are occasionally shifted, so that the same guns are not always used for this purpose; cases have occurred, where this has not been done, erosion, due to saluting charges, has necessitated the condemnation of the gun.

Guns for Mercantile Auxiliaries and in Reserve.

All guns in reserve, including those for mercantile auxiliaries and those allocated to particular ships, should have their bores coated with the following mixture:

Such guns should be examined at frequent intervals (to see that this mixture has not been removed from the bore), and by the Naval Ordnance Department annually.

Annual Examination.

At the annual examination the mixture will be removed, and after ascertaining that the bores are free from rust, they will be recoated. If the mixture be found too stiff for convenient application it should be warmed until of a suitable consistency.


In ships of small fighting efficiency, the larger guns should have their bores lacquered with the following mixture:-

They are then hermetically sealed at the breech and muzzle, and no examination or inspection is necessary.

Block, 6 and 8 pdr. Guns.

When the block is removed from a 6 or 3 pdr. gun for storage purposes the mainspring should be released from tension.


Careful attention should be paid to all lubricating holes in breech mechanisms. Before lubricating they should be cleaned with a wire; care must be taken to replace the small screws where so fitted. Vaseline should not be used, as it is likely to cause stiffness and missfires, especially in semi-automatic guns.


1. Before submerging, the gun and mounting are to be prepared as follows:--

(a) All fittings, including sight bracket and breech fittings, are to be in place. The telescope only is to be removed.

(b) All parts which are not actually working parts are to be coated with a mixture composed of 1 part of white lead and 2 ½ parts of tallow.

(c) The pivots, trunnions, breech screw or wedge, sights, and striker, should be lightly oiled.

(d) The bore of the gun is to be lightly oiled. Attention is called to Gunnery Order No. 66, dated 1st April, 1915:--

"Bores of Guns - Lubrication of. --As the result of experiments following on the breaking up of lyddite shell in a 4 in. and 12 pdr. gun, it has been demonstrated that the accidents were probably due to heavy lubrication of the bore for a short distance from the muzzle. Care is therefore to be taken that an excess of oil or vaseline is not left in the bores of guns. The bores of guns which have been filled with lubricant for preservation are to be thoroughly cleaned before firing."

(e) Vaseline or heavy lubricant of any sort is not to be used in the bore of the gun or on any part of the mounting.

2. When the Gun is exposed to the action of the water.

(a) If circumstances will permit the gun should be worked in elevation and training once every 24 hours.

(b) Opportunity should be taken on emerging from the water, according to circumstances and the time available, of stripping the breech mechanism, lubricating the pivots, and working the percussion firing gear. Particular attention should be paid to cleaning the bore.

(c) The steel non-working parts should have the rust removed and be re-treated with white lead and tallow. This mixture should be kept ready for immediate use as opportunity offers.

(d) In order to keep the gun and mounting in a serviceable condition, the whole of the above process should be carried out every three days if practicable.

(e) After prolonged service at sea, the mounting should be stripped for thorough examination. This examination will be made by an Ordnance Artificer of the parent ship.

(f) On arrival at a dockyard or private yard to refit application for examination of the gun and mounting should be made to the Captain of the Gunnery School or Captain Superintendent.

(g) A report on the state of the gun and mounting is to be forwarded on these occasions.

(h) It is not necessary to pass the sponge through the bore before firing immediately after emerging from the water, unless some foreign substance is in it. A visual examination of the bore is always to be made before firing the first round.


For the preservation and lubrication of gun mountings, sights, etc. in the dockyard, a mixture of light mineral oil and mineral grease is employed in the proportion of 1 gallon of oil to 2 lbs. of mineral grease, the mineral grease being first boiled and the oil added, or alternatively both being boiled together, the former being the safer practice.

This compound is lightly applied with a paint brush, and it is found that it can be easily wiped off two or three months after its application.

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Last Updated: 10 February, 1999.