I doubt in the middle of war they would fill in all the nicks and marks made to the cannon. wether or not this is a reference of a different cannon, it's stil a cannon and if you keep your references to only 1 type of cannon you may not have as much variety when it comes to giving it life. it was a reference for wear and…
Aright Aright guys, I'll try some game work, starting with the cannon, will be going back and forth between the cannon and the cannon. @grimm - thanks for that pic, really awesome :) Uploaded with ImageShack.us added a chain and doing some more render playing.
Cannons and bells are not made of the same metal, nor are they the same thickness. Also not all metal that cannons are made of actually rust, so be careful with that as well. Try to find some reference of cannons and sculpt from that so you get more believable results.