This is a bit of an oddity. I think it's posed - the men are too relaxed - and there is what appears to be an information card or something similar leaning against the base of the mount. 115th AAS was raised in mid-1917 and went to France so I would have expected a detachment to be wearing helmets, not caps, when they were in action.
The whole thing shows how lessons have been learned from the earlier versions. The stabilising beams are now fitted with a screw-jack with a load-spreading foot so packing isn't required under the large, wooden pads. The gun is the 13-pdr 9-cwt - the sleeved-down 18-pdr - which is easily recognised by the barrel being considerably longer than the recuperator.The breech dimensions were retained so the muzzle velocity of the 13-pdr shell was significantly increased, something that was much needed to reduce the flight time to the target. With a 6-cwt gun the shell could take over 30s to be where a plane was predicted to be and even with the relatively slow speeds of WW1 aircraft there was a lot a pilot could do in that sort of time.
The oddly-shaped object by the wheel is a detachable mudguard and its height shows how much the platform could roll during travel - the centre-of-gravity would have been very high indeed thanks to the gun, which weighed several tons. The platform is lower on a gun-lorry than for other types of coach-building because the base of the mount is bolted directly to the chassis members, meaning the top of the rear wheels sit in slots. When travelling this is bolted over the hole. With earlier versions, the men had to step around the hole as they worked but later ones had a much shallower cover that replaced the mudguard and the lorry at the IWM Duxford has these in place. How much they were used in practice I have no idea because they wee about two inches high and could have been more of a tripping hazard than leaving the slot open, I would have thought.
It's possible this was taken in England before they embarked for France or in the rear areas (they were under the LoC for control) after they arrived. Perhaps someone will recognise the plaque on the wall as British or French. My gut feeling is that this is a personal photo record of some of the men of this detachment, perhaps taken by a local photographer rather than an official one.
Edited by Rockdoc, 04 March 2012 - 08:00 AM.