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Hi

I recently acquired a 71B with 2 modules labeled "M109A/M198 1 of 2" and "M109A/M198 2 of 2" . They also have a label saying "HTI-SD-0113.00 Made in England". Does anyone know what these are?

Laurence Carr

I believe they were used for the M109 FAMILY OF HOWITZERS to help calculate artillery fire. The M109A4 and M109A4+ are fully tracked, armoured vehicles used to provide close artillery support. The vehicles are air-transportable and carry a total of 36 rounds. The 155mm cannon is designated the (M185). The assembly comprises a breech ring, bore evacuator, muzzle brake and a tube cannon. The breech mechanism is a semi-automatic, screw block type, designated for separate loading ammunition. Breech opening and closing is accomplished by utilizing the energy of counter recoil and closing, by laminated torsion springs. Firing is accomplished by the mechanism (M35) which uses cartridge type primers, fired by a continuous pull percussion mechanism. The mount consists of a cradle assemble that mounts the hydraulic variable recoil mechanism, S.A. cam, recuperator, counter recoil buffer, upper and lower rotors, limit stops and dust shields. Pad and brackets are available for mounting the fire control instruments.



http://www.eme421.com/m109.html

These are artillery targeting modules. If you do a catalog, you will see things like "target" and others that have to do with coordinates, etc.

I asked a military discussion forum once if they ever used the HP-71B and got an affirmative. The dates that the person said he used them matched the era of these machines.