Cutting the barrels perfectly square.
I can't believe I'm giving you this information, but if your bound and determined to do it, do it right. Place the side of each barrel up against something with a long corner you can hold it against in a rock solid steady manner, where can i find this? you say, it's called a door jam. Using the edge of the door jam, guide a pencil down the length of the side of each barrel, and if you want it done correctly these lines have to be exactly on the outside edge of each barrel. A little high or low and all the effort you take to do the other steps right won't mean $h!t. Now that you have your two reference lines make a mark where you want to cut the barrel + plus 1/64th of an inch measuring from the breech end. An exacto blade turned backwards is perfect for making this mark, just through the bluing so you have a very fine, shiny mark. Cut a strip of paper from the edge of a piece of paper 1/4 inch wide and long enough to wrap around both barrels. Now this strip of paper has two long edges, the one cut at the factory, and the one you cut. We want to use the edge that was factory cut to mark our barrel. So wrap the paper so the the paper band is covering the portion of the barrel you want to keep and the factory edge returns on itself perfectly and just covers the marks you made and secure one end of the paper strip to itself where it meets with tape. Now slide the whole band back just far enough to expose your cut marks and put a few drops of elmers glue along the edge you cut so that they are half on the paper and half on the barrel and allow the glue to dry so it doesn't move during the next step. Grab your self a sharpie, silver on a blued barrel, black on a ss barrel and follow the factory cut edge of the paper strip, put half the pen tip on the paper and half on the barrel, the idea is to use the paper as a stencil. Don't press too hard or the sharpie will bleed through the paper and you won't have a sharp line when you remove the paper band. Cut the barrel leaving just a sliver of the sharpie mark, I highly recommend a band saw (go slow and apply a few drops of motor oil every so often to prevent barrel warping and blade wear)for this, but if you can actually summon forth some patience you could do a nice job with a high quality hack saw blade. Now use a fine file that is at least twice the width of the barrel and file until you have just removed the sharpie mark all the way around. You now have two barrels that are "plumb" cut. Finish of with some emery cloth lighty to remove burrs and bob's your uncle.
And may god have mercy on your soul.
