The 12 pound mountain howitzer was the most commonly used cannon and it was originally designed to be disassembled and packed into the mountains by horseback hence the name Mt'Howitzer. The later model Mt'Howitzer's like the one we make were made to be pulled by horses on a carriage. Our Mt' Howitzer is on a first model prairie carriage but it can also go on a second model prairie carriage or a field carriage or a pack carriage but as of right now we only build the first model prairie carriage for this cannon. If you would like to buy a barrel for the carriage you already have we can make the barrel to fit your carriage we can make custom trunnion sizes for oddball carriages just send us a print or email it to use and we will make for you. The standard bore size for a Mt' Howitzer is 4.625 with a 3' chamber most reenacter want a smaller chamber so it will not need so much powder to fire it we have had a couple of people get there barrel chambers 2" with a 4.625 bare only 4" back from the front so it looks full size from a distance but get's a big bang by having a small chamber.