As the Ships were commissioned into the Royal Navy, they would have had the Mausers removed, and replaced by Lee-Enfields of earlier Models, as was common in the Royal Navy. The Mausers were used for “Mine Destruction”…Picked marksmen on small ships would “shoot off” the “Horns” of Sea Mines to explode them, once the Mine cable had been cut and the Mine floated to the surface.
As to the marking “Mine” etc, the ammo was probably loaded with care, to get good accuracy (lots selected on “Figure of merit” sytem): shooting a Mine Horn of about one to two inch diameter, six inches long, at a distance of over 100 yards, would take some accuracy…using Open sights. And the mine is Bobbing up and down in the water…very good shooting is required.
As shown, the label is a typical ISAA approved Service Label in layout and style. All ammo supplied to the British War Office carried such labels if it was made in Britain or the Commonwealth (then Empire).
A simple packet and a photograph have just enlarged my knowledge of Chilean ship’s armament three times…
Regards, Doc AV
Mines float on the surface either bacause their moorings have broken or have been cut by a Minesweeper. In most cases (if manufactured in accordance with the relevant international treaties) these mines were supposed to become inert when the tension in the mooring wire was lost, but nobody I know wearing a Blue Suit would ever trust that. The usual disposal method was to sink them without approaching too close. Once sat on the bottom they were usually way out of reach of any vessel. Exploding them would be nice but, as you say, required very accurate shooting and a good dose of luck. This was further complicated by the mix of moored mines, some of which were Switch Horns, some glass phial electrical generators, some accoustic etc. Later the game was further complicated by ship count clocks and contact, magnetic, accoustic and pressure triggers. Most of these would not respond to a bullet. So, whilst a big bang (in the distance) would be a good result, putting enough holes in the casing to make the damned thing sink was good enough. The typical moored mine is a cylindrical drum of HE inside a spherical bouyancy chamber casing so punching holes in the casing should sink it. In later years (post WW2) the RN used Bren guns for mine sinking.