I like krieger barrels. My gunsmith likes them a lot and I know of a competition shooter that has great success with them. This explains it all:
Barrel Making
We rifle by the single-point cut rifling process. Although our machines are state of- the-art; the process itself is the oldest and slowest method of rifling a barrel. The cutter removes .0001 inch or 100 millionth of an inch at each pass; thus taking several hundred passes to rifle a barrel. This method produces perfect concentricity between bore and groove, a very uniform twist rate, and induces no stress into the steel. This is why we can gain all the benefit of treating the steel beforehand. There is no additional stress put into the steel by the machining or rifling method that later has to be relieved. Along the same lines we do absolutely no straightening of our barrels as this would only put stress right back into the steel.
Our barrels are lapped after reaming to remove the tool marks and then lapped again after rifling. It has been said that if a barrel is cut rifled correctly, it doesn't have to be finish lapped, and to some extent this is true. It should not have to be lapped to obtain uniformity of dimensions. This should come from the tooling and procedures used. But there is a slight improvement in the finish, and the lay of the finish is in the direction of the bullet travel so fouling is greatly reduced; and they clean much easier. It takes longer to finish lap, but it makes a better barrel. We are lapping to finishes under 16 micro inch in the direction of the bullet travel. In contrast the government requires only a 32 micro-inch finish on its M-14 National Match barrels.
Our barrels are held to a tolerance of zero to + .0005 over the nominal bore and groove dimensions, but the dimensions are uniform within .0001 throughout the barrel and never bigger at the muzzle than at the breech. There may, however, be a slight flare at each end of the barrel from the tools entering and exiting. This is why you should always remove at least an inch from the muzzle when fitting any barrel.
