VOLUME TWO--------AUGUST 2002
SHOOTIN', HUNTIN' AND RELOADIN'
WITH THE OL' MISSOURI
This month I
want to talk about using the Stoney Point Cartridge
Overall Length Gauge. This gauge enables us to measure the exact length of our
loaded cartridges from the bullet’s ogive to the
base of the cartridge case.
Rifles can vary considerably in the length of the throat. (the
smooth portion of the bore between the end of the case neck and the beginning of
the rifling lands) They can also be very particular about the distance of bullet
jump from the case neck to the rifling. By varying the distance the bullet has
to jump, we can often increase the accuracy of our
handloads in a given rifle.
This is where the OAL (Over All Length) gauge comes to our rescue! Use of the
gauge allows us to experiment with seating depth, and more importantly, to
duplicate the exact distance that gives the best accuracy.
First, just follow the clear instructions that come with the gauge to determine
the actual length of the cartridge when the bullet is touching the lands. Record
this measurement, as it becomes the base line for knowing exactly how much we
are manipulating seating depth.
Note that this requires a caliber specific "Modified Case", a bore size specific
"Bullet Comparator Insert and Body", and an accurate dial caliper. All are
available at major shooting supply stores. My favorite supplier in Spokane is
Sportsman's Warehouse. They have several locations in the Northwest and you can
visit their web site at
to see if there is one near you. (These guys buy in such quantity that they can
usually sell you this stuff cheaper than the manufacturer will.) You can also
check out Stoney Point's web site at
should you elect to order directly from them.
competitors have found that seating bullets from 20 to 40 thousandths of an inch
short of the lands will often give the best accuracy for a given load.
However, only shooting YOUR rifle with YOUR load will tell you for sure which
OAL gives the best groups.
CAUTION: As always, the load you are using may
not be safe in any firearm other than the one used to develop the load. Also,
seating bullets directly against the rifling can sometimes increase the
pressures to dangerous levels for an otherwise safe load!!
consideration for repeating rifles, is that the
magazine length may limit the OAL of the cartridge, so be sure and check this as
you go. We, of course, want our general hunting ammo to cycle through the
magazine, but, if a longer length proves to be a tack driver, you can always
single load those for target or varmit shooting.
The rifle I am
using for testing the OAL gauge is a Ruger Model
Number One single shot in .25-06 caliber. With this rifle I am using the gauge
for bolt actions or single shots with straight on access to the chamber. There
is also a curved model available for use with lever action, pump, and
I won't publish specific load data, but I can tell you the load I am using in
the Ruger contains a 75 grain
Hornady V Max bullet over Hodgdon's H-414
Powder. My chronograph clocks the load I am using at about 3550 fps 12 feet from
the muzzle of the 26 inch barrel.
I plan to start my testing with the bullets seated to a depth that gives the
cartridge the same length from case head to bullet tip as a factory round. I
will then seat further out in .010 inch increments until I am .020 inch from
touching the lands. As I shoot groups for each seating depth I should find the
right formula and then be able to repeat that depth for my most accurate load
with that set of components.
It should be noted here that some bullets in light weights for caliber, may not
be long enough to give the case neck a good grip when seated close to the
rifling, so watch for this also. I may have this situation with the 75
gr bullet I am using. We shall see!
I'll report on the range testing with the ol’
Ruger in a future newsletter as soon as I finish the
So. . .
‘Til next time, Keep ‘em
shootin’ straight, shoot ‘em
often, and above all, BE SAFE!!!!!
THE OL' HILLBILLY
2002 - All Rights Reserved
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