- Location
- The Conservative part of Ontario
Oversized Dies?
o prevent “oversizing”
brass, die makers recommend
the time-honored
technique of trial-and-error
testing for minimum resizing.
In other words, you back the
die off a full turn after screwing
it down to touch the ram/shellholder
at the top of its stroke.
That position would push a
case fully into the die for fulllength
resizing. But your rifle’s
chamber might be slightly bigger
than this. Since the fired
brass has already stretched to
that size, why squeeze it back?
It’ll only stretch more on the
next firing.
Keeping cases close to chamber
dimensions improves accuracy,
too, helping to align
bullet to bore. This is why
some target shooters like to
neck size only, using the camming
action of the bolt to force
the tight cartridge into battery.
Hunters, however, need ammunition
that chambers smoothly
and easily, so minimal body sizing
is a good idea. To achieve
this minimum sizing with your
dies and brass, set the resizer
die a full turn too high as described
above. Run a case into
the die, then chamber it in the
rifle, noting how hard the bolt
closes. An oversized case will
make for a tight fit and hard
bolt closure. Screw the die
down a bit more and try again,
continuing the process until
the case fits with just a hint of
pressure. The die is now set for
minimum resizing. Lock it in
place, using a small plate of
steel between shellholder and
die base to square the base in
the threads.
I generally set up all my dies
this way, but recently found
two that wouldn’t minimally
size cases even with
full die/shellholder
contact. What is
going on? One of
three things. Either
the die was reamed
too large or the rifle’s
chamber was reamed
too small or the
shellholder is too tall.
The simplest solution,
according to engineer
Patrick Ryan
at Redding, is to
sand the bottom of
the die slightly. Tape
a sheet of 220 wet or
dry sandpaper to a
flat slab of glass or
steel plate and run
the base of the offending
die over it in
a figure eight pattern,
measuring frequently
with calipers
to check your progress.
Also test progress
by resizing cases as above
and running them through
your rifle. Alternatively, you
could sand down the top of the
shellholder, but then it wouldn’t
be the right height for your
other dies – unless you reset
them all. If more than one set
of dies seems oversized, the
shellholder might be the
problem. Go ahead and sand it
thinner.
www.loaddata.com
Tech Tips
Ron Spomer
•
T
o prevent “oversizing”
brass, die makers recommend
the time-honored
technique of trial-and-error
testing for minimum resizing.
In other words, you back the
die off a full turn after screwing
it down to touch the ram/shellholder
at the top of its stroke.
That position would push a
case fully into the die for fulllength
resizing. But your rifle’s
chamber might be slightly bigger
than this. Since the fired
brass has already stretched to
that size, why squeeze it back?
It’ll only stretch more on the
next firing.
Keeping cases close to chamber
dimensions improves accuracy,
too, helping to align
bullet to bore. This is why
some target shooters like to
neck size only, using the camming
action of the bolt to force
the tight cartridge into battery.
Hunters, however, need ammunition
that chambers smoothly
and easily, so minimal body sizing
is a good idea. To achieve
this minimum sizing with your
dies and brass, set the resizer
die a full turn too high as described
above. Run a case into
the die, then chamber it in the
rifle, noting how hard the bolt
closes. An oversized case will
make for a tight fit and hard
bolt closure. Screw the die
down a bit more and try again,
continuing the process until
the case fits with just a hint of
pressure. The die is now set for
minimum resizing. Lock it in
place, using a small plate of
steel between shellholder and
die base to square the base in
the threads.
I generally set up all my dies
this way, but recently found
two that wouldn’t minimally
size cases even with
full die/shellholder
contact. What is
going on? One of
three things. Either
the die was reamed
too large or the rifle’s
chamber was reamed
too small or the
shellholder is too tall.
The simplest solution,
according to engineer
Patrick Ryan
at Redding, is to
sand the bottom of
the die slightly. Tape
a sheet of 220 wet or
dry sandpaper to a
flat slab of glass or
steel plate and run
the base of the offending
die over it in
a figure eight pattern,
measuring frequently
with calipers
to check your progress.
Also test progress
by resizing cases as above
and running them through
your rifle. Alternatively, you
could sand down the top of the
shellholder, but then it wouldn’t
be the right height for your
other dies – unless you reset
them all. If more than one set
of dies seems oversized, the
shellholder might be the
problem. Go ahead and sand it
thinner.
www.loaddata.com
Tech Tips
Ron Spomer
•
T
