The following is from Kreiger’s website:
WHO WE ARE
Krieger Barrels Manufactures precision single-point
cut-rifled barrels in calibers ranging from .20 through 4 Bore for the best
target shooters and custom rifle builders in the world.
THE STEEL
There is nothing so important to the making of a good barrel
as the steel that a barrel maker uses. Early on we realized we had to give the
mill our own specifications for our steel, accept the higher cost, and then
have each lot heat tested as it came in to assure compliance to our strict
requirements.
We started by having exhaustive metallurgical tests run on samples of both good
and bad steel to determine, on a molecular level, what made good barrel steel.
Having determined this, we met with representatives of the steel mill, the
metallurgist, and the heat treater to discuss the results of our findings and
to implement the changes that we needed.
For over 30 years this process has never stopped, and Krieger Barrels continues
to test and perfect the steel composition and heat treatment regime. We do not
offer multiple grades of steel. All of our steel must meet the same standards.
We do offer most of our barrels in a choice of either stainless steel or chrome
moly. Our stainless and chrome moly barrels are both held to the same standards
from initial steel mill quality to final inspection of dimensions and finish.
SINGLE-POINT CUT-RIFLING
We rifle all of our barrels using 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. It’s
also the most accurate. The cutter removes approximately .0001 inch, or 1
ten-thousandth of an inch, at each pass, thus taking several hundred passes to
rifle a barrel. This method produces almost perfect concentricity between bore
and groove, a very uniform twist rate, and induces no stress into the steel
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 hand-lapped again after rifling. It has been said that if a
barrel is cut-rifled correctly, it does not 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 to the finish achieved by finish lapping, and the lay
of the finish is now in the direction of the bullet travel so fouling is
greatly reduced, and cleaning is made easier. It takes longer to finish lap,
but we do it because 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.
