The 155mm Canon court Mle 1904 Tir Rapide Rimailho (the name coming from the designer, Colonel Rimailho) was meant to be a very manoeuvrable heavy-calibre gun with with a high rate of fire, and so it also turned out, but the price was considerable mechanical complexity. The gun itself was a normal box-trail, two-wheeled carriage with a short barrel and recoil system of the hydro-pneumatic type.
It had a screw breech that was before its time as it was semi-automatic ("automatic opening and semi–automatic closing"), and it was of course this semi-automatic loading that gave the gun its high rate of fire. Putting it simply: when the gun recoils, the breech opens automatically by the force of the recoil, and is then held back while the gun tube goes back into normal position. As the tube goes forward, a loading tray comes out from underneath it and cartridge and shell are dropped into it. Then the firing lever is pulled: both the loading tray and breechblock run up to the gun breech, ramming the shell and cartridge into position. The breech then closes and locks and the gun is discharged.
A well-trained crew could fire 15 42.9kg grenades a minute with this gun, which is very impressive, by any standard. The muzzle vwlocity was 320m/sec. It was also pretty light for its calibre (3.2 tons) and the elevation was good: +41° maxium. The only real problem with the Canon de 155 court Mle 1904, beside its complicated loading mechanism, was the range. The maximum range of some 6,000 meters was pretty good by 1914, but it was outranged by all German guns of comparable calibre, and it was slowly replaced by other, more long-ranged guns, like the 155mm GPF.
The gun below can be seen in the fantastic Army Museum in Brussels, a museum not to be missed by anyone interested in the Great War.
There are no model kits in any scale or material of this gun, at least not that I know of.