Barrels.... If the barrel has thin walls and is dovetailed, even the minimum depth its not uncommon to find a loose spot in the bore at the dovetails with 24" of the breech and perhaps even farther up. At least if the barrel is properly proved. These are like the small dimples seen in SAA Colt Cylinders at the lock bolt cuts from proving. A heavier wall barrel will not be as effected if at all by this. If anyone wants to test this, use a jag with a short bearing surface and a tight oiled patch and slide it up and down the bore with a GOOD, stiff rod with a bearing handle. Most people will be very surprised..... Drilling holes and staking the underlugs can form slight "bumps" in the bore.....
The extra machine work done in making a really light barrel or a swamped barrel or a 1/2 octagonal barrel cannot help the accuracy. For example a big name custom CF barrel maker drills a blank for a Garand barrel, does all the exterior machine work, then reams and cut rifles the barrel. This will maintain the bore dimension much better than doing all the machine work AFTER the bore is finished.
A button rifled barrel barrel has incredible stresses set up even if its normalized when it arrives at the plant. A barrel that is button rifled then machined with a taper will invariably have a larger bore at the muzzle than the breech. I have never seen it fail. If the black in drilled and reamed and buttoned and then normalized it will then maintain its internal dimensions when tapered. 1/2 octagonal barrels that are not normalized before machining are even worse.
For a dedicated match rifle use a straight heavy barrel made of a piece of quality steel that is properly stress relieved. The LENGTH increases the sight radius and this will aid in accurate sight alignment. They also hang better and wobble slower than short barrels in offhand shooting. A barrel heavy enough to really dampen the "whip" as it might be called is too heavy too shoot well off hand in most bore sizes.
Dan
