Not my work, but this has good info.....
Cast Bullet Basics For Military Surplus Rifles
By C.E. Harris Rev. 9-6-93
Cast bullet loads usually give a more useful zero at practical
field ranges with military battle sights than do full power
loads. Nothing is more frustrating than a military rifle that
shoots a foot high at a hundred yards with surplus ammo when the
sight is as low as it will go!
Do NOT use inert fillers (Dacron or kapok) to take up the excess
empty space in the case. This was once common practice, but it
raises chamber pressure and under certain conditions contributes
to chamber ringing. If a particular load will not work well
without a filler, the powder is not suitable for those conditions
of loading.
Four load classifications from Mattern (1932) cover all uses for
the cast bullet military rifle. I worked up equivalent charges
to obtain the desired velocity ranges with modern powders, which
provide a sound basis for loading cast bullets in any post-1898
military rifle from 7 mm to 8 mm:
1. 125-gr., plainbased "small game/gallery"
900-1000 f.p.s., 5 grains of Bullseye or equivalent.
2. 150-gr. plainbased "100-yd. target/small game",
1050-1250 f.p.s., 7 grs. of Bullseye or equivalent.
3. 150-180-gr. gaschecked "200-yard target"
1500-1600 f.p.s., 16 grs. of #2400 or equivalent.
4. 180-200-gr. gaschecked "deer/600-yard target"
1750-1850 f.p.s., 26 grs. of RL-7 or equivalent.
None of these loads are maximum when used in full-sized rifle
cases such as the .30-40 Krag, .303 British, 7.65 Argentine, 7.7
Jap, 7.62x54R or .30-'06. They can be used as basic load data in
most modern military rifles of 7 mm or larger, with a standard-
weight cast bullet for the caliber, such as 140-170 grains in the
7x57, 150-180 grains in the .30 calibers, and 150-190 grains in
the 8 mm. For bores smaller than 7 mm, consult published data.
The "Small Game or Gallery" Load
The 110-115-gr. bullets intended for the .30 carbine and .32-20
Winc
hester, such as the Lyman #311008, #311359 or #311316 are
not as accurate as heavier ones like the #311291. There isn't a
readily-available .30 cal. cast small game bullet of the proper
125-130-gr. weight. LBT makes a 130-gr. flat-nosed, GC bullet
for the .32 H&R Magnum which is ideal for this purpose. I
recommend it highly, particularly if you own a .32 revolver!
The "100-Yard Target and Small Game" Load
I use Mattern's plainbased "100-yard target load" to use up my
minor visual defect culls for offhand and rapid-fire 100-yard
practice. I substitute my usual gaschecked bullets, but without
the gascheck. I started doing this in 1963 with the Lyman
#311291. Today I use the Lee .312-155-2R, or the similar tumble-
lubed design TL.312-160-2R. Most of my rifle shooting is done
with these two basic designs.
Bullets I intend for plainbased loads are blunted using a
flatnosed top punch in my lubricator, providing a 1/8" flat which
makes them more effective on small game and clearly distinguishes
them from my heavier gaschecked loads. This makes more sense to
me than casting different bullets. Bullet preparation is easy.
I visually inspect each run of bullets and throw those with gross
defects into the scrap box for remelting. Bullets with minor
visual defects are tumble-lubed in Lee Liquid Alox without
sizing, and are used for plain-based plinkers. Bullets which are
visually perfect are sorted into groups of +/- 0.5 grain used for
200 yard matches. Gaschecks pressed onto their bases by hand
prior running into the lubricator-sizer.
For "gaschecked bullets loaded without the gascheck," for cases
like the .303 British, 7.62 NATO, 7.62x54R Russian and .30-'06 I
use 6-7 grains of almost any fast burning pistol powder,
including, but not limited to Bullseye, W-W231, SR-7625, Green
Dot, Red Dot, or 700-X. I have also had fine results with 8 to 9
grains of medium burning rate pistol or shotgun powders, such as
Unique, PB, Herco, or SR-4756 in any case of .303 British siz
e or
larger.
In the 7.62x39 case use no more than 4 grains of the fast-burning
powders mentioned, or 5 grains of the shotgun powders. These
make accurate 50-yd. small game loads which let you operate the
action manually and save your precious cases. These
plinkers are more accurate than you can hold.
Repeated reloading of rimless cases with very mild loads results
in the primer blast shoving the shoulder back, unless flash holes
are enlarged with a No.39 drill to 0.099" diameter. Cases which
are so modified must NEVER be used with full-power loads! ALWAYS
identify cases which are so modified by filing a deep groove
across the rim with a file and label them clearly to prevent
their inadvertent use. For this reason I prefer to do my
plainbased practice shooting in rimmed cases like the .30-30,
.30-40 rag, .303 British and 7.62x54R which maintain positive
headspace on the rim and are not subject to this limitation.
The Harris "Subsonic Target" Compromise
Mattern liked a velocity of around 1250 f.p.s. for his "100-yard
target" load, because this was common with the lead-bullet .32-40
target rifles of his era. I have found grouping is best with
nongascheck bullets in military rifles at lower velocities
approaching match-grade .22 Long Rifle ammunition. I use my
"Subsonic Target" load at around 1050-1100 f.p.s. to replace both
Mattern's "small game" and "100-yard target" loads, though I have
lumped it with the latter since it really serves the same
purpose. Its report is only a modest pop, rather than a crack.
If elongated bullet holes and enlarged groups indicate marginal
bullet stability, increase the charge a half grain and try again.
If necessary increasing the charge no more than a full grain from
the minimum recommended, if needed to get consistent accuracy.
If this doesn't work, try a bullet which is more blunt and short
for its weight, because it will be more easily stabilized. If
this doesn't do the trick, you must change to a gaschecked bullet
and a heavier load.
The Workhorse Load - Mattern's "200-Yard Target"
My favorite load is the most accurate, Mattern's so-called "200-
yard target load". I expect 10-shot groups at 200 yards, firing
prone rapid with sling to average 4-5". I shoot high-
Sharpshooter/low-Expert scores across the course with an issue
03A3 or M1917, shooting in a cloth coat, using my cast bullet
loads. The power of this load approximates the .32-40,
inadequate for deer by today's standards.
Mattern's "200-yard target load" is easy to assemble. Because it
is a mild load, soft scrap alloys usually give better accuracy
than harder ones such as linotype. Local military collector-
shooters have standardized on 16 grains of #2400 as the
"universal" prescription. It gives around 1500 f.p.s. with a
150-180-gr. cast bullet in almost any military caliber. We use
16 grains of #2400 as our reference standard, just as highpower
competitors use 168 Sierra MatchKings and 4895.
The only common military rifle cartridge in which 16 grains of
#2400 provides a maximum load which must not be exceeded is in
the tiny 7.62x39 case. Most SKS rifles will function reliably
with charges of #2400 as light as 14 grains with the Lee .312-
155-2R at around 1500 f.p.s. I designed this bullet especially
for the 7.62x39, but it works very well as a light bullet in any
.30 or .303 cal. rifle.
Sixteen Grains of #2400 Is The Universal Load
The same 16 grain charge of #2400 is universal for all calibers
as a starting load. It is mild and accurate in any larger
military case from a .30-40 Krag or .303 British up through a
.30-'06 or 7.9x57, with standard-weight bullets of suitable
diameter for the caliber. This is my recommendation for anybody
trying cast bullet loads for the first time in a military rifle
without prior load development. I say this because #2400 is
not position sensitive, requires no fiber fillers to ensure
uniform ignition, and actually groups better when you just
stripper-clip load the rifle and b
ang them off, rather than
tipping the muzzle up to position the charge.
Similar ballistics can be obtained with other powders in any case
from 7.62x39 to .30-'06 size. If you don't have Hercules #2400
you can freely substitute 17 grains of IMR or H4227, 18 grs. of
4198, 21 grs. of Reloder 7, 24 grs. of IMR3031, or 25.5 grs. of
4895 for comparable results. However, these other powders may
give some vertical stringing in cases larger than the 7.62x39
unless the charge is positioned against the primer by tipping the
muzzle up before firing. Hercules #2400 does not require this
precaution. Don't ask me why. Hercules #2400 usually gives
tight clusters only within a narrow range of charge weights
within a grain or so, and the "universal" 16 grain load is almost
always best. Believe me, we have spent alot of time trying to
improve on this, and you can take our word for it.
The beauty of the "200-yard target load" at about 1500 f.p.s. is
that it can be assembled with bullets cast from the cheapest
inexpensive scrap alloy, and fired all day without having to
clean the bore. It ALWAYS works. Leading is never a problem.
Once a uniform bore condition is established, the rifle behaves
like a .22 match rifle, perhaps needing a warming shot or two if
it has cooled, but otherwise being remarkably consistent. The
only thing I do after a day's shoot is to swab the bore with a
couple of wet patches of GI bore cleaner or Hoppe's, and let it
soak until the next match. I then follow with three dry patches
prior to firing. It only takes about three foulers to get the
03A3 to settle into tight little clusters again.
"Deer and Long Range Target" Load
Mattern's "deer and 600 yard target load" can be assembled in
cases of .30-40 Krag capacity or larger up to the .30-'06 using
18-21 grs. of #2400 or 4227, 22-25 grs. of 4198, 25-28 grs. of
RL-7 or 27-30 grs. of 4895, which give from 1700-1800 f.p.s.,
depending on the case size. These charges must not be used in
cases smaller than the .3
03 British without cross-checking
against published data! The minimum charge should always be used
initially, and the charge adjusted within the specified range
only as necessary to get best grouping. Popular folklore
suggests a rifle barrel must be near perfect for good results
with cast bullets, but this is mostly bunk, though you may have
to be persistent.
I have a rusty-bored Finnish M28/30 which I have shot
extensively, in making direct comparisons with the same batches
of loads on the same day with a mint M28 and there was no
difference. The secret in getting a worn bore to shoot
acceptably is remove all prior fouling and corrosion. Then you
must continue to clean the bore "thoroughly and often" until it
maintains a consistent bore condition over the long term. You
must also keep cast bullet loads under 1800 f.p.s. for hunting,
and under 1600 for target work.
A cleaned and restored bore will usually give good accuracy with
cast bullet loads if the bullet fits the chamber THROAT properly,
is well lubricated and the velocities are kept below 1800 f.p.s.
The distinction between throat diameter and groove diameter in
determining proper bullet size is important. If you are unable
to determine throat diameter from a chamber cast, a rule of thumb
is to size bullets .002" over groove diameter, such as .310" for
a .30-'06, .312" for a 7.62x54R and .314" for a .303 British.
"Oversized .30s" like the .303 British, 7.7 Jap, 7.65 Argentine,
7.62x39 Russian and frequently give poor accuracy with .30 cal.
cast bullets designed for U.S. barrels having .300 bore and .308
groove dimensions, because the part of the bullet ahead of the
driving bands receives no guidance from the lands in barrels of
larger bore diameter. The quick rule of thumb to checking proper
fit of the forepart is to insert the bullet nose first into the
muzzle. If it enters to clear up to the front driving band
without being noticeably engraved, accuracy will seldom be
satisfactory.
The forepart is not
too large if loaded rounds can be chambered
with only slight resistance, the bullet does not telescope back
into the case, or to stick in the throat when extracted without
firing. A properly fitting cast bullet should engrave the
forepart positively with the lands, and be no more than .001"
under chamber throat diameter on the driving bands. Cast bullets
with a tapered forepart at least .002" over bore diameter give
the best results.
Many pre-WWII Russian rifles of US make, and later Finnish
reworks, particularly those with Swiss barrels by the firm SIG,
have very snug chamber necks and cannot be used with bullets over
.311" diameter unless case necks are reamed or outside turned to
.011" wall thickness to provide safe clearance. Bullets with a
large forepart like the Lee .312-155-2R or Lyman #314299 work
best in the 7.62x54R, because the forcing cones are large and
gradual. Standard .30 cal. gaschecks are correct. Finnish
7.62x54R, Russian 7.62x39 and 7.65 Argentine barrels are smaller
than Russian 7.62x54R, Chinese 7.62x39, Jap 7.7 or .303 British
barrels, and usually have standard .300" bore diameter, (Finnish
barrels occasionally are as small as .298") and groove diameters
of .310-.3115".
In getting the best grouping with iron sighted military rifles,
eyesight is the limiting factor. Anybody over age 40 who shoots
iron sights should to equip himself with a "Farr-Sight" from Gil
Hebbard or Brownell's. This adjustable aperture for your
eyeglass frame was intended for indoor pistol shooters, but it
helps my iron sight rifle shooting, and adds about 5 points to my
score!
So now you have enough fundamentals to get started. If you want
to have fun give that old military rifle try. You'll never know
the fun you've been missing until you try it!
