OBERMEYER RIFLED BARRELS
Quality Rifle Barrels Since 1962

23122 - 60th Street
Bristol, Wisconsin  53104

Profiles and Contours

Contours

The final contour turning operation normally occurs after the blanks have been drilled, before
reaming and rifling. Some barrels in small sizes may be finished from a larger, basic-turned blank. The
contour is turned on a tracer lathe and is proportional for the length of the blank. If you want a
smaller or larger muzzle diameter the breech end will change the same amount unless another
pattern is used or the setup is modified on the template bar. The breech end of the blank is turned
to a nominal diameter of 1.275 inches for work-holding or chucking purposes and cannot be
machined in the same operation as the contour turning. This unfinished portion of the blank is
generally less than two inches in length, although it may extend to several inches, depending on the
specific geometry of the requested profile. This area is to be machined by the installer.

Note: The sketches below are generic illustrations of each major type, not scaled mechanical
drawings.


Sporters






Original Sporter:  This is a medium barrel with a 0.650”-0.700” muzzle diameter, similar
to the 1903 Springfield contour.

Basic Sporter:   This barrel is based on the Remington varmint pattern. A long, straight
section beginning one inch back from the muzzle has a diameter of 0.800”. The
diameter of the barrel at the breech end of the long section, just below the shoulder, is
approximately 0.930”. A popular variant of this pattern is one made with 6 flutes. At the
muzzle end of the fluted version, the one-inch long cut-off section has a reduced
diameter of 0.750” in order to fit the blank into an indexing fixture.

Remington 700:  This is the Remington factory profile with a muzzle diameter of
approximately 0.660”. I leave a cylindrical section at the breech so it can be fitted to
most actions.

Weatherby Sporter:  This is based on the Weatherby .25 caliber barrel and finished to an
approximate muzzle diameter of 0.620”. Heavier variants of this pattern are available
by increasing the muzzle diameter to as much as 0.750”. The typical 12-flute version of
this barrel has a muzzle diameter of 0.690”.

D - 3:  This is a popular sporter profile having a 0.625” muzzle diameter at 24”, and it
weighs about 3 lbs. The pattern allows the barrel to be turned somewhat lighter, like
the #2,  with a 0.600” muzzle at 24”; the resulting blank weighs about 2.75 lbs. Another
option is to leave the barrel somewhat heavier, like the #4, with a 0.650” muzzle at
26”; the resulting blank weighs about 3.5 lbs.

KDF K15:  This is a pattern for large-caliber barrels in the .35 to .40 range. It also looks
good as a heavy sporter barrel. The muzzle diameter is usually 0.675” to 0.715”.

Winchester Model 70:  Patterns for this barrel are available in both old and new styles, as
well as a featherweight version.

Other common sporter patterns:  Sako, original Holland & Holland, Fabrique Nationale (FN)
with steps, Remington Model 722, Husquavarna, Ruger Model 77 police/varmint, Ruger
#1, Pac-Nor varmint, etc.


Palma Barrels







OK #2:  This barrel is based on Otto Weber’s Palma pattern. The diameter of the barrel
one inch back from the muzzle is 0.82” in order to accommodate the popular 0.812”
front sight mounting bands. The diameter of the blank at the breech end of the long
section, just below the shoulder, is approximately 1.05”. The 6-flute variant of this
profile has become popular in 30” length target barrels for use in competitions where
weight limits are a consideration. A 30” fluted barrel of this type, installed as a .308,
will weigh approximately 5 lbs.


Straight-Taper Target Barrels






AMU: The Advanced Marksmanship Unit contour is our basic (and most popular) target
pattern; it has a taper of 0.0132” per inch. It has an approximate diameter of 1.25” at
the breech end of the taper and a diameter of 0.90” 28 inches from the breech end,
which would also be one inch back from the muzzle. A typical 28-inch blank of this type
will weigh approximately 7.2 pounds if round, or 5.6 pounds if fluted.

AMU Plus: The AMU Plus (AMU+) contour also has a 1.25” diameter at the breech end of
the taper, but the taper itself is reduced to 0.007” per inch. The idea of the AMU Plus
pattern is to provide sufficient stock material to allow a barrel to be fluted while
retaining the weight of an AMU-pattern round barrel. For example, a .30 caliber fluted
barrel of this type would weigh approximately 6.9 pounds. An AMU Plus blank may also
be manufactured without flutes as a very heavyweight round barrel.

Remington Target: The Remington 40X target contour is manufactured with a taper of
0.012” per inch. It has an approximate diameter of 1.20” at the breech end of the taper
and a diameter of 0.87” 28 inches from the breech end, which would also be one inch
back from the muzzle. A typical 30-inch fluted blank of this type, popular for long-range
prone rifles, will weigh approximately 5.9 pounds.

Remington Plus: The Remington Plus (Rem+) contour also has a 1.20” diameter at the
breech end of the taper, but the taper itself is reduced to 0.007” per inch. The idea of
the Remington Plus pattern is to provide sufficient stock material to allow a barrel to be
fluted while retaining the weight of a Remington-pattern round barrel. For example, a
6.5mm fluted barrel of this type would weigh approximately 6.1 pounds. A Remington
Plus blank may also be manufactured without flutes as a heavyweight round barrel.

Other common straight-taper target patterns: Winchester Model 70 (0.014” taper per inch),
California (0.017”/0.018” taper per inch), Hunter Benchrest (0.021” taper per inch), etc.


Service Rifle Barrels








M-14 (M1A): The heavy barrel target pattern for M-14 barrels includes a step for
operating rod bands having a nominal inside diameter of 1 inch.
                                                                                        








M-1 Navy: The M-1 Navy contour represents our heavy target pattern for the famous
"Garand" rifle.









M-16 (AR-15): The M-16/AR-15 contour is available for "leg" guns suitable for Civilian
Marksmanship Program (CMP) Excellence-in-Competition matches. Match rifle variants
are manufactured with longer lengths and larger (approximately 0.920”) muzzle
diameters.