One wonders how ANYTHING was ever accomplished before lathes were invented!

If you want to tackle this yourself, fIrst thing you need to do is scribe an accurate line around the barrel. If there is not too much taper I think I would try using a pipe cutter just to make a line to follow. Once you have a line that matches up on itself EXACTLY, I would take a hacksaw and carefully go over the line, then when everything lines up EXACTLY again, make it deeper then when you have a 1/8" groove carefully and slowly cut through the barrel. Use a new 24 TPI bi metal blade and plenty of oil.

Nothing wrong with learning how to do things yourself, with what you have available, just remember that you need to make up for those shortcomings with care, patience, and thoughtfulness.

I've done 4 or 5 with a hacksaw and they all looked and shot great. One very odd barrel was on a chinese norinco jw15 .22 bolt action . The bore is not even close to the center of the barrel. with the naked eye you can see that it is drilled off center. I cut the gun down to "chipmunk" size for my daughter, and crowned the barrel with a brass screw. It will easily shoot 1/2 inch groups at 50 yds. I've also done high power rifles with the crowning tools from brownells. 1" to 1 1/2 inch groups were the result. Same as before I cut the barrel. As stated before if you screw it up a smith can always take a little more off and square it up. I like to tinker, so I think it's a worthwhile project.
Good shooting,
Weagle

If the rifle is a "beater" and you are a die hard do it your self guy I would try it, but I would cut the bbl no shorter than 19". That way if you mess it up you could take it to a pro and have it cut to 18".