The Emperor's Cannon

I have just finished making this master model of a French 12-pounder for Michael Perry's Franco-Prussian War range. This one took over forty hours of intense concentration and that's not including the more leisurely time spent in research. I'm happy with the result, in terms of historical accuracy, detail and practicability for the wargamer who is the end customer. But I found this quite heavy going at times, and after the Prussian 6-pounder I have promised to do, I would need a lot of persuading to do any more artillery masters.

The model is built entirely from styrene, apart from the drag-brake chain. (What's that? See below.) I gather some people who build such masters use various modelling putties, and good luck to them, but that approach is outside my skill-set, so to speak. Using styrene strip and rod enables me to trim and sand each of the hundreds of pieces down to an accuracy of a fraction of a millimetre and they are easily assembled with liquid styrene cement. (The main sections of the barrel and trail assemblies are brass-rodded together for strength.) We end up with a master of seven parts in this case: the carriage, the barrel, two wheels, the trail-spike, the elevating screw and the brake chain. These parts are just pushed together here to show what the completed thing will look like

The downside of a styrene master for the manufacturer is that you can't put it into a vulcanising machine to make a production mould, because it won't stand the high temperature involved. So in intermediate stage is required:  The parts are first moulded in resin, which reproduces them very faithfully, and these resin parts will stand up to the heat of the vulcanising process. The customer ends up with a little kit of seven white metal parts to assemble with superglue, but it's obvious where everything goes and there are locating holes and pins on the parts for a positive fit. 

The historical gun is formally designated a "Piece de 12 rayee (rifled), Modele 1858", itself a conversion, by adding rifling on the La Hitte principle, of the smoothbore Model 1853 gun-howitzer. The latter had actually been designed by the Emperor Napoleon III himself, quite an artillery expert in his younger years, hence it was known as the "canon de l'Empereur". This was the state of the art when it came to field artillery in the 1850's: a "shell-gun" firing both solid cannonballs and spherical explosive shells. It was copied in the USA as the "12-pounder Napoleon" and served as the mainstay of Civil War artillery. Gun technology was moving forward very fast at this time however, and an officer called La Hitte devised a practical system of rifling that approximately doubled the range. The main field piece built on this principle was the newly-designed 4-pounder, a gun I modelled earlier. It was felt some heavier metal was required for the corps and army-level reserve artillery and so 1853 12-pounders were bored out to fill this role.

Whilst we're on 19th-century artillery-lore, they struggled a bit with terminology at this time. Traditionally guns were designated by the weight of solid iron cannonball they fired, so a 12-pounder fired a ball that actually weighed 12 pounds. The calibre corresponding to this size of shot was around 120mm, but that was first used to designate artillery pieces shortly after the Franco-Prussian War. Gunners were so familiar with the traditional labels that they kept them even when the guns actually started to fire projectiles of quite different weights. Firstly the spherical explosive shell with a timer fuse and then the "cylindro-conical", ie pointy shell with either a timed or "explode on impact" (if you're lucky) fuse. So the gun here fired a shell weighing something like 25 pounds, but it fitted the bore which had once accommodated 12-pound iron cannonballs. That's the real reason for these confused designations, though the water was, and still is, sometimes muddied by the argument that 25 pounds is "basically 12 kilogrammes". 

Finally, if your patience with artillery-lore isn't exhausted, I'll explain what the "drag-brake" or "drag shoe", the chain business on the side of 17th to19th artillery pieces is all about. It answers a problem that most of us wouldn't think of. When on the march, if the gun (or a wagon or whatever) is being towed down a sharply-sloped road, it rolls forward and can bang into and injure the nearest pair of horses in the team. So the drag shoe is deployed. It is a kind of skid or ski on the end of a retaining chain, which was fastened underneath one wheel to stop it revolving. You would think they'd need one on both wheels for this to work, but apparently not: the gun skidded and slid down the slope, moved by the tow horses rather than gravity, and at the bottom the drag shoe is hooked up again. This fitting isn't something you often see on a wargames model, and I had to think about how to make it in a way that will cast and can easily be assembled by the customer. But being pleased with the arcane knowledge of what the heck it's for (a secret now shared with you, dear reader), I couldn't resist making an effort to model it. So probably I shouldn't moan about how long it took, should I?