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Frequently Asked
Questions
- Why cryogenic (cold)
treatment?
Cold
treatment has been used for a long time in many different
industries. Swiss time pieces gained their reputation for accuracy
in part because Swiss watchmakers originally stored their watch
parts in mountain caves for a period of three years or more, but
wound up with superior parts. That's well before there were cold
treatment plants and research.
At
this point in time no one can scientifically explain why it works,
and believe me there has been extensive research done. Research
indicates that in the iron/carbon system there are very fine
carbides that precipitate during the cryogenic process. These add
to significant wear resistance. Residual stresses are also
eliminated. But no one knows the scientific why of it and both Los
Alamos National Laboratory in the US, and the University of Trento,
Italy among others, note that there is something happening in the
sub microstructure that is not well understood.
Until
the early part of the 20th century we didn't understand why steel
got hard by quenching and tempering. That didn't stop us from using
hardened steels. We didn't understand exactly why airplanes flew
for the first 25 years of flight. The Wright brothers observed the
way that wings created lift, but didn't know why (their work was
strictly empirical). This certainly didn't ground aircraft until
they could explain the why.
The
critics who refuse to use cryogenic processing because there is no
scientific evidence of its existence are missing the boat. The
proof is overwhelming. In our industry the top quality custom
barrels are cold treated, some twice in the production process. A
cold treated barrel shoots the same hole hot or cold. The point is
that cryogenic processing has been shown to reliably increase the
wear resistance of virtually all metals and some plastics, and
totally stress relieve the material, and the results are
repeatable.
Blueprinting refers to the machining performed on an action to make
all of the machined surfaces nearly perfectly true to the bolt
raceway. Production machining tolerances are generally 0.005" plus
or minus. When blueprinting an action we bring those tolerances to
a maximum of 0.0001" plus or minus. This is done by a machinist on
a precision lathe equipped with a 4 jaw independent chuck. The
receiver is centered in a truing sleeve that is adjustable by means
of 4 front and 4 rear jaws, the rear having 2 locations (for long &
short actions). Centering the receiver in the truing sleeve is
accomplished by inserting a mandrel into 2 perfectly fitting
bushings that have been inserted into the 2 bearing surfaces of the
bolt raceway, and using 2 test indicators placed at opposite ends of
the exposed mandrel end achieving axial alignment. When both
indicators show .0001" or less run out at the same time & in the
same rhythm you have perfectly aligned the center line of the bolt
raceway axis with the lathes rotating axis. The receiver face, and
the receiver locking lugs are cut at exactly 90 degrees to the bolt
raceway line. The receiver threads are then single point re-cut so
that they are also true to the bolt raceway line. The receiver way
is polished for smooth bolt travel. The bolt is then put in a
precision bolt fixture that insures that the bolt is centered on the
firing pin hole. The fixture is then centered in a 4 jaw lathe chuck
with test indicators, and the bolt face and the locking lugs are
then cut true. The bolt and receiver locking lugs are lapped to
mate the surfaces insuring 95% plus contact at exactly 90 degrees to
the bore line. The firing pin spring channel is reamed & honed
which reduces spring drag and shortens lock time.
The
accuracy of any rifle manufactured will be enhanced by a
professionally installed bedding. Think of your body and your rifle
stock as nothing more than a gun platform. Of the above two
components the rifle stock is the one that can be altered to
eliminate any and all up or down, or forward and backward movement
of the action/barrel assembly. The action/barrel assembly should
also have the minimum amount of contact with the stock so that it is
allowed to resonate. If you want your rifle to shoot accurately it
is one of the "must do" processes in the progression toward that
goal.
We have seen that
best method of bedding to be the use of a barrel bedding block. This is especially true when bedding receivers with a large
ejection/feed port & a large (staggered box feed) magazine port. There is so much metal removed that there is no way that this type
of receiver can be rigid. When you use a barrel bedding system
you are no longer using the receiver to support the weight of the
barrel, and you are supporting the barrel/receiver assembly at the
heaviest, most rigid part of the assembly (the first 4" of the
barrel in front of the receiver) & much closer to the balance point
of the assembly. The receiver assembly and the majority of the
barrel is then free floated. This allows the use of any weight
& contour barrel with consistent, predictable results.
Custom barrel manufactures that have a deserved reputation of
producing Match Grade barrels, are through out the manufacturing
process testing the steel to ensure its quality, and somewhere in
the manufacturing process they also cryogenically treat the barrel
to stress relieve the steel. Factory production techniques, due to
volume, aren't able to adhere to the strict quality control
techniques employed by custom barrel makers. You don't have to be
an expert to see the difference. All it takes is a Hawkeye Borescope, and even to the uninitiated eye the differences between
the two are dramatic.
Pros - Reduced barrel weight, and faster dissipation of heat. To some
people there is a certain amount of eye appeal to a fluted barrel.
Cons - The action of a cutter pounding on the exterior of the barrel is
akin to pounding on the barrel with a hammer. The end result
will be a certain amount of deformation of the bore with a resultant
loss of accuracy.
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