These are original British Army issue Firing Pin Protrusion (FPP) Gauges, No4 Mk2, for the 7.92mm BESA tank MG.

The gauges were used to measure the amount that the tip of the firing pin protruded from the breech block face when in the fired position, thus ensuring that there was enough to fire the cartridge, but not enough to puncture the primer. These are primarily an Armourers tool, however they are listed in the Illustrated Spare Parts Lists (ISPL's) for the BESA and so may have been included in the Complete Equipment Schedule (CES) for the tank or the MG.

The Mk2 gauge is a modification of the Mk1 FPP gauge and has had the 'no-go (larger) end changed to 1.45mm by grinding. As these are modifications of existing gauges, the boxes of 10 gauges in which they are packed have a wide variety of manufacturers, dates and styles within the same box. The majority of the gauges found to date have 1950's dates marked on them.

All gauges are in excellent to new condition (see pictures).

Unit of sale 1 gauge.

British Army Part No C2/SM568. Stock No ARMRSTOOL 54.

PLEASE NOTE; The gauge is 'Gauge No4 Mk2' - this refers to the gauge only, it is for the BESA 7.92mm MG ONLY , it is NOT for the NO4 Rifle! These are also available in sealed boxes of 10 elsewhere in this section.