Bad Idea! Unknown quality of pipe with extensive welding of the "plug" and additional large weld spots along the bore area! A proper barrel can be made of certain types of pipe steel which can be very strong, A turned and press fitted plug equal to the bore diameter can then be welded in place properly and this unit placed inside a cast or turned and bored solid stock to achieve a tremendously strong unit.(I'm not an expert, please contact a reputable re-enactment group for details.) Better yet, contact a cannon manufacturer like South Bend Replicas who can line you up with what you need. Their catalog is worth whatever they're asking for it. Join a War Between The States artillery unit and drill 'til you're sick of it! Building a cannon is a major undertaking, and the safety of yourself, your gun crew, and anyone else around is paramount in the construction and use of a piece. To do it right will cost money, time and dedication, but there is in my honest opinion, no greater achievement. You will provide a hobby for your entire gun crew and educational opportunities for the general public. State parks and Civil war battlefields usually welcome artillery crew and I have seen them donate cannon grade powder to help defray the cost of firing. There are lots of smaller places to conduct drill and live fire exercises. I recall one such practice weekend on an old battlefield near Rentlesville, Ok. We only had four guns and there was only a small field an woods all around. It was the best camp ever! My wife and daughter and I worked on gun crews and we camped in our wedge tent and listened to the trains moan in the distance late at night. Our crews received hands on experience with competent officers and quality full scale 6pdr pieces. I hope you can enjoy artillery as much as I have; keep it safe and be a credit to our legacy. Cpl. George Briggs, Ist Ark. Lt. Artillery, Ret.