The 64 prs were first introduced into the Navy but became obsolete by the 1870s and were then employed for land service. The forts of the Gosport Advanced Lines were armed with the 58 cwt. gun on their main faces and the 71 cwt. gun in their Haxos. Most were mounted on no. 18 platforms for the faces and casemate platforms for the Haxos. Those of the Portsdown Hill line received the 71 cwt. version on no.18 platforms for main armament. None were fitted to the Haxos. The 64pr. fired a common shell to a distance of 4,000 yards using a charge of 8¼ lbs at an elevation of 11 degrees.Seventeen of the lighter 64prs. were mounted on a pattern II Moncrieff disappearing carriage for use at Malta. The 64 pr. now on the main rampart at Fort Nelson is a conversion from the 58 cwt. Dundas pattern 32 pr. dating from 1847. Rifled with three grooves, it bears the monogram of Queen Victoria in relief on the second reinforce. The left trunnion is marked with RGF 101 1 1873 whilst the right trunnion bears the usual cross hairs for elevation purposes. The first reinforce is inscribed with a Broad Arrow and the weight 59-1-14. The face of the bore lining tube at the muzzle is stamped R.G.F. Iron. It has a calibre of 6.29 inches, length of 9ft. 6 inches and overall length of 10ft. 5 inches. The carriage and platform were built in the workshops of the County Museum service at Chilcombe House, Winchester. This was all made possible by a generous donation from the Dutch firearms collector Henk Visser. An armament return for Fort Nelson dated 1884 shows that all of the 64 prs mounted were the 71 cwt version rather than the 58cwt example that is now mounted for display purposes.
The Portsdown Artillery Volunteers firing the 64pr. R.M.L.
mounted on a number 18 blocked-up traversing platform, on the West Rampart at Fort Nelson.
The Portsdown Artillery Volunteers with the Middlesex Regiment at Fort Nelson 2002