Model Expo has several metal gun kits for sale to build your own 1/16 scale replica of your favorite artillery piece.  The Whitworth Cannon kit is a model of the breech loading 12 pounder that was popular in the American Civil War.  Assembly time is 5-10 hours, just perfect to while away winter days. (It's 5 below F outside right now, I should get one of these!)  Only $99 bucks US, with a generic limber available for $99 and a caison for $75.  Also available is a Gatling Gun kit, also $99.  They have a January combo deal of a cannon and limber for only $99, so check that out.)

Model Whitworth cannon

Model Expo has been in business since 1976, and is proud of their contribution to the modelling industry.  You can get everything you need in the way of tools to finish your project on their website.  They have a Facebook  page with quite a fan base,  and a YouTube channel. Be sure to check out their gallery of user finished model kits.  If you really need to use up some winter hours you can try the Sopwith Camel aircraft kit (with twin Vickers guns). That should keep you busy for awhile.

Model of Sopwith Camel