1. How precise does an octagonal barrel have to be? I have an indexing faceplate on a heavy-duty wood lathe, and was thinking of mounting a grinder on a carriage to grind the flats (very slowly, to prevent heat distortion). In effect, it would be like using a surface grinder—take a pass, rotate 180º, take another pass...
I know the old muzzle-loader barrels were shaped using a file, pre-mills. (I have a schwamped Damascus barrel that had to have been welded around a mandrel, then filed to be an octagon. The rifle is dated 1842, and was converted from flint to percussion—the frizzen spring is still there. I used to shoot it, and it was very accurate.)
2. Common sense tells me that if the flats are not concentric with the bore, the barrel is not going to heat up evenly. I've also read that barrel blanks are not always concentric, so would a non-concentric octagonal barrel be any worse?
Am I over-thinking this?
Richard