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Sight bar marked: "R.M.L. 2.5 IN. R.G.F. /|\ 1898 RECIP'G M.V. 1440 F.S." Graduated on the right face with a range scale up to 4,000 yards and on the left with an elevation scale up to eleven degrees.

This example has South African provenance, having been purchased from a vendor in Pietermaritzburg, and may have belonged to a Natal Field Artillery or 10th Mountain Battery gun. Both units, consisting of twelve screw guns in all, were stationed in Maritzburg when hostilities broke out. A photograph of a Boer gun crew with a captured 2.5-inch R.M.L. gun, shows a similar sight in use. The Boers had six of these pieces; two captured from Jameson and four from No 10 Mountain Battery at Nicolson’s Nek.

Ian Cross (Pietermaritzburg), in his article on No 10 Mountain Battery, published in the South African Military History Journal (June 2009), notes “A special tangent sight with a reciprocating bracket was issued for use in cases when ground prevented the axis of the trunnions from being horizontal”.

According to the Priced Vocabulary of Stores (1898), reciprocating sight were only made for the 2.5-inch R.M.L. and 4-inch Howitzer R.M.L.





The principal of a reciprocating sight is that it can be adjusted so as to remain vertical when a gun is on sloping ground. The bronze mount (D) fits into the sight socket at the rear of the barrel. The blued steel carrier (E) is attached to this mount via a dovetail joint (C), which forms an arc in the vertical plane. When the locking lever (B ) is released, the carrier is free to slide along the dovetailed groove, allowing the artillerist to rotate the sight until it is vertical. This is done with the aid of the spirit level (A). As the carrier moves around the arc, it rotates about an axis which aligns with and is at the same height as the foresight. This system ensures that the backsight is always correctly aligned with the fixed foresight, which remains tilted with the gun.























The description below appears to be of an earlier model of the sight, as it refers to a rack-and-pinion, connecting the mount (bracket) with the carrier (socket), which is not present on the example above.

Handbook for 2.5-inch R.M.L. Steel (Jointed) Gun (1888)

Each gun is also provided with a special tangent sight, with clamp and reciprocating bracket, which fits into the ordinary tangent sight socket. This arrangement admits of compensation in laying the gun should the axis of the trunnions not be horizontal, or should the junction-nut not be properly screwed up.

On the rear face of the bracket is pivoted a socket provided with a spirit level and a pinion gearing with a rack on the bracket.

The socket carries the special tangent sight, which can thus be adjusted into a vertical position and secured by means of a clamp fitted on the pinion. The bracket may be used with either Mark I or II gun, and on either side of the gun.

The sights for Mark II gun are interchangeable with those for Mark I when used in sets of tangent and foresight, but the line of sight is slightly lower.

The former may be distinguished by having “Sir W. Armstrong & Co” stamped on the deflection leaves.


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From the Navy & Army Illustrated magazine

From the Navy & Army Illustrated magazine