It is best to
ignite it with
a Large Rie
Magnum
primer.”
bullets more tightly than the
original brass. Actually, such a
slight difference is nothing to
worry about and the same
loads can be used safely in
both lots.
The case capacity of the .338
Win. varies even more from
one maker to the next.
Measuring water capacity
from half a dozen different
brands revealed that weight
ranged from 73.8 to 78.6
grains. W-W Super and
Federal were highest and more
or less identical.
As with any belted magnum,
care should be taken that the
sizing die does not set
shoulders back. This is
important with belted brass
since it seldom headspaces on
the belt in the way it is
supposed to. Sizing cases to
headspace on the shoulder not
only prevents head separations,
but extends case life.
As usual when working up
loads for the .338, I miked
fired cases just forward of the
belt in determining
comparative pressures.
Contrary to what some believe
the best accuracy with a
magnum case usually comes
with near or maximum loads.
Carrying out load development
using my Ruger Number One, I
found that new factory
Super-X loads measured
0.5135" in diameter at this
point, so I restricted my
handloads to an additional
expansion of .0005". One
doesn't shoot away a lot of .338
ammo, so in my current
Mauser rifle, about whichmore later, I am still using my
original brass and not a single
case has developed an
incipient head separation or
enlarged primer pocket.
With the large charges and
type of powder the .338
thrives on, it is best to ignite it
with a Large Rifle Magnum
primer. Changing primers,
however, had no affect upon
velocities or pressures, but I
settled for using CCI 250
magnum primers which are
normally recommended for
heavy charges of slow burning
powders, and particularly the
spherical types which I have
dropped from use.
The best propellant powders
for the .338 are, I have found
those with medium burning
rates such as AR2209, RE-19,
RE-22, and AR2213Sc - all are
excellent. Winchester's slow
burning W-785 Ball powder
also worked well, but has since
been dropped in favour of
W-780, which I haven't tried.
I've been impressed with the
accuracy and velocity I got
with 65gn of AR2208 behind
the Barnes 185gn TSX which
churned up 3124 fps and
consistently grouped 3 shots
under one MoA. The Hornady
225gn Spire Point and 75gn of
AR22113sc got a velocity of
2830fps. Other loads are listed
in the table.
A problem with very long
.338 bullets- in particular the
Barnes 225gn and 250gn Sierra
SBT as well as the 300gn
Barnes FMJ - is that in holding
to the maximum allowable
overall cartridge length, they
must be seated altogether too
deep in the case, bullets bases
often projecting below the
case shoulder. Increased
weight and length is not the
only factor, however, since
bullet shape also has a bearing
on how far down into the case
their bases can extend, even
with bullets of the same
weight, and this deep seating
definitely affects both
pressures and velocities by
reducing usable powder space.86 | SPORTING SHOOTER _ MAY 2018
4 & 5
Heimo Petzl bagged
this trophy bull with
Nick ’s Ruger Number One. The
.3 38 with a stout 250gn bullet is
deadly buffalo medicine.ON THIS PAGE
PRACTICAL
RELOADING4
5