Say you needed to make a rifled barrel. I'll not worry about optimal twist rates for the benefit of theoretical discussion.
Do you think it would be feasible to take a length of 2" SCH-80 (most probably conduit since that's what seems to be the cheapest), and a length of 1-1/2" SDR-26 or thinner (possibly SDR-31 or something like that). Then, you do the following.
Come and inch up from one side of the pipe, and make two or three 1/2" or 1/4" wide marks. Going off your twist rate, glue some pieces of string to these marks and wrap around the pipe. So, if you wanted a 1:60 twist rate, you would draw a line going all the way down 60", and wrap the string around once on it's way over there. Then, you would mark the line formed by the two pieces of string with marker, remove the string, and cut out the sections on either side of this strip. There will still be about an inch on either side of the cuts, so the pipe shouldn't collapse or deform severely. After this, the pipe is coated in some SLOW DRYING PVC cement, and sleeved into the 2" SCH-80. When it dries, cut off the ends of the pipe to remove the unrifled sections at the ends, and et voila: a rifled barrel.
It sounds doable, to me at least. What do you guys think?








