The 1/2" conduit is a bargain if you can find it without a rough seam inside. The one problem with it is that it will rust if it isn't kept dry. You might try waxing the bore. I did this with a fifty cal by rubbing parafin on a peice of paper and then wadding it into a football shape and working it back and forth in the bore with a rod. It takes a while to get a polished finish but it can be done.