Dec 122017
 
Reloading specs for NATO 7.62mm round.
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Reloading specs for NATO 7.62mm round.
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Contents of the 762X39.TXT file


SUMMARY DATA ON 7.62x39 - Revised CEH 4-23-90 -
This is additional data which was not included in the recent
American Rifleman article.
I have reloaded thousands of rounds of this 7.62X39 ammunition with
both cast bullets and jacketed, and have fired them in the AK and
the SKS. I got frustrated with the AK as accuracy of these seems
to be generally poor, but the SKS is more reasonable, and is a real
bargain these days. It seems the best an AK will do is about 5-6
moa, and the SKS with good ammo will do 3-4, sometimes better. The
gas ports on these guns are larger than they need to be for
reliable functioning, so light cast bullet loads down to about 1400
f.p.s. work fine. None of the common cast bullet designs are quite
right for this caliber, because the necks are so short, and the
groove diameters run large.

I designed a bullet and had a custom mould made by NEI of Canyon
City, OR, which they identify by the number 155.311GC. This bullet
is .92" long and weighs 155 grs. in linotype or about 160-grs. in
wheelweight alloy. I designed it with the idea to produce the
heaviest bullet which could be loaded effectively without the GC
poking into the powder space, and which would be big enough on the
forepart to fill the large throats on the AK and SKS, as well as
in the 7.62x54R Russian, .303 British, 7.65 Argentine, 7.7 Jap,
etc. It has only one grease groove, and a crimp groove .26" from
the base. The rear driving band casts .313", the front band .311"
and the forepart ahead of the crimp groove is .310", and the ogival
radius starts from this large diameter in order to maximize bearing
length. The bullet has proven very accurate, and outshoots ball
ammo in the SKS or AK with any reasonable load, and in a bolt-
action rifle will stay under 1-1/4" 10-shot groups at 100 yards
taking bullets out of a 5-cavity gang mould.

The Sierra 125-gr. .308" spitzer seems to be the most accurate of
this weight, and shot better than the Hornady 123-gr. .310" and
the 150-gr. Spire Points in either .308" or .312", which they make
for the .303 British. The popular 150-gr. spitzers intended for
the .30-'06 or .308 do not expand at 7.62x39 velocities, but
bullets intended for the .30-30 work well. Of these the 125-gr.
Sierra JHP flatnose and the 130-gr. Speer FN seem to work the best.
I have gotten good accuracy with the 150-gr. Sierra MatchKing
bullets in by boltgun of this caliber which I built on a Sako
action, but you might consider using match bullets a costly
absurdity in an AK or SKS.

I also tried some of the cheap surplus 7.62 NATO M80-type bullets,
but these shot very poorly, about 4-5" in the boltgun at 100 yds.,
and almost twice that in the AK, and about 6" in the SKS. I prefer
cast bullets for most of my shooting in this caliber, but if I were
to buy jacketed bullets the 125-gr. Sierras in either FN or spitzer
style would be my choices, with the 130-gr. Speer flatnose .30-30
bullet also strongly in the running, and the 123-gr. Hornady spire
point for the 7.62x39 is also OK, as are 150-gr/ .30-30 bullets.


I don't have the pressure gun to work with which I did when at
Ruger, but in my experience with several rifles, these loads should
be OK. When I did pressure tests with H322 and Accurate Arms 2230
and Hodgdon H335 it appeared you couldn't get enough into the case
with a 125-gr. bullet to get into any trouble, and a caseful made
a highly satisfactory load. H322 used to be about the cheapest
powder around, and works very well in this caliber. I use 28 grs.
with a 125-gr. bullet for about 2200, and 25 grs. with a 150-gr.
bullet for about 1900. With my cast bullet I use 24 grs. for about
1850, which works very well.

Accurate Arms now has their powder AAC1680 which is very similar
to the Olin 680 Ball powder, though slightly slower. The best
load with 1680 and the 155 gr. NEI cast bullet seems to be around
16 grs. in the SKS, which gave me about 1400 f.p.s., and 3" groups
at 100 yds. 18 grs. gives 1630 f.p.s. and about 4" groups in the
SKS, with 19 grs. velocity is about 1700 and groups opened up to
over 5", which I consider unsatisfactory. I did just two strings
with the Olin 680 for comparison with the NEI bullet at 18 and 19
grs., respectively, which gave 1810 and 1930 f.p.s. I would not
exceed 19 grs. of Olin 680 with the 155-gr. cast bullet, or 23 grs.
with a 125-gr. jacketed one, as these are both full loads. With
ACC2230 you can use all the powder the case will hold with a 125-
gr. jacketed bullet, about 30 grs., and no problem. With a 155-
gr. cast bullet start around 26 grs., up to 28 grs. maximum, for
2050 f.p.s.

I have also used IMR-4895 with good results. About 17 grs. is the
minimum charge which will function the SKS with a 160-gr. cast
bullet, but you can stuff the case with all the powder it will hold
and you can't get in any trouble. It works well with cast bullets
from 150 grs. up.

As for reloading the Berdan primed cases, it isn't worth the
trouble.

Charge Establishment for NEI 155.311GC cast CEH design bullet, WW
alloy quench-cast from mould, as-cast dia. .313", tumble lubed in
Lee Liquid Alox. No GC used except where noted. Midway cases,
Remington 9-1/2 primers, Ctg. OAL 2.20" taper crimped in C-H die
from Midway Arms. Test firings in Norinco AKS with 16.4" barrel.
H4198 Velocity Remarks
(Grains) @ 15 ft.
14.8 1252, 39Sd feeds, ejects OK, but unburned pdr.
granules cause occasional failures
of breech to close fully.
17.4 1490, 47Sd functions OK
18.5 1578, 31Sd functions OK
20.4 1715, 47Sd function OK, slight leading w/o GC
22.0 1880, 30Sd GC bullet, function OK, no leading
22.6 1909, 27Sd GC bullet, function OK, no leading
accuracy decays above this charge.


Charge Establishment for Accurate Arms 1680 propellant in SKS with
NEI 155.311GC bullet, as above.

Grains Vel. @ 15' ES for 5-shot group @ 100 yds., (cm)
16.0 1422, 21 Sd 4.5 cm
17.0 1629, 25 Sd 7.7 cm
19.0 1710, 7 Sd 11.7 cm

Olin W680 for comparison
18.0 1810, 15 Sd no group recorded
19.0 1932, 18 Sd " " "

Olin 680 with 122-gr. PS Ball bullet pulled from 101-71 Chicom
ammo.
23.0 2381, 11 Sd Midway case with large primer F210
23.0 2332, 14 Sd BELL case with small primer F205

PS Ball for comparison, velocities from SKS with 20.5" barrel
Chicom 101-71 2415, 11 Sd
East German 04-77 2448, 11 Sd


MANUFACTURER'S CODES FOR 7.62X39 MM AMMUNITION
CODE COUNTRY CODE COUNTRY
01 WEST GERMANY A79 SOUTH AFRICA
3 USSR AD INDONESIA
04 EAST GERMANY aym CZECHLOSLOVAKIA
05 EAST GERMANY bxn CZECHLOSLOVAKIA
10 BULGARIA CAVIM VENEZUELA
11 (PRC no serifs)
Yugo has serifs
13 CUBA CBC BRAZIL
17 USSR FN BELGIUM
21 POLAND HP AUSTRIA
22 ROMANIA IK YUGOSLAVIA
23 HUNGARY IZ CZECHLOSLOVAKIA
31 PRC Lapua FINLAND
031 PRC NK YUGOSLAVIA
51 PRC (letter N backwards)
60 USSR nny YUGOSLAVIA
61 PRC PMC SOUTH KOREA
71 PRC PMV CUBA
81 PRC PP YUGOSLAVIA
93 NORTH KOREA
101 PRC
141 PRC PPU YUGOSLAVIA
270 USSR PT FINLAND
343 POLAND VPT FINLAND
351 unk. (PRC?) RPR ROMANIA
501 PRC SO FINLAND
539 USSR ZV CZECHLOSLOVAKIA
711 USSR
Numeral headstamps containing the number 1 (one) WITHOUT SERIFS
are usually PRC.
EAST-BLOC BULLET TIP COLOR CODES:
Tracer - Green API - Black tip/red ring
API - Black tip/black annulus (PRC)
PRC API will have lacquered or copper washed steel case.

BRASS CASE WITH THIS CODE and nny headstamp is Yugo proof

Analysis of 7.62x39 mm powder from Chinese PS Ball Factory 71,
1983: Is single-base, containing 0.4% K2NO3 flash retardant
bulk density .90 grams/cc, cylindrical grains .041 long, .0205"
diameter, NOT perforated, diphenylamine stabilizer, compares most
closely to IMR4475 in granulation and burning rate.


ACCURACY TEST OF 7.62x39 mm SKS RIFLES BY CEH 1/30/88
Average of four consecutive 10-shot groups at 200 yards, iron
sights. Two targets each rifle shot with Yugo M67 123-gr. lead core
ball Two targets each rifle shot with PRC 101-71 Type PS steel core

Rifle No. Origin Avg. ES No. of Hits on "E" Silhouette
641991 USSR pickup 11.75 33x40 (rifle condition worn/good)
If zero had been 1/2 mil left this rifle would have scored 40x40
hits.
J8138 USSR pickup 11.38 38x40 (rifle condition
worn/good)
M3976 USSR pickup 13.77 35x40 (rifle condition
worn/good)
15082 PRC 15.16 37x40 (rifle condition
excellent)
25636 PRC 12.17 35x40 (rifle in new condition)

01724 PRC 12.72 39x40 (used, VG condition)
Avg. six SKS rifles 12.82 36x40 90% hits

RESULTS BY AMMO TYPE: SIX RIFLES POOLED, 12 TEN-SHOT TGTS. @ 200

Chinese PS Ball 12.70 108x120 = 90%
Yugo M67 Ball 12.89 109x120 = 90%
25636 RESHOOT 300 YDS. 17.28 29x40 40 rds. PS ball 101-71
This is typical 300 yd. performance for SKS

Previous Test of USSR SKS carbine serial no. 641991 by CEH and JBR,
March, 1983, average of five consecutive 5-shot groups at 200 yds.

[email protected]' Smallest Largest Average
USSR PS 2297 7.50 12.87 10.59
60-K (1950) 31 Sd 10-shot tgts.
This USSR PS test shows good agreement with other firings of SKS
rifles of 1/30/88, which included this one. Note influence of
ammunition quality below:
Lapua Ball 2370 3.31 7.50 5.94
(Berdan) Better than typical
SKS with PS Ball.

CEH FIRINGS OF AKM FOR COMPARISON WITH SKS

AKM Factory 66 #305163 17.25 32x40 (rifle condit.
excellent)
PRC 101-71 PS Ball shot at 200 yds., typical for AKM and AK47.

Previous CEH test of Maadi AKM imported by Steyr for NRA, March,
1983.

Average of Five consecutive 5-shot groups at 200 yards.
[email protected]' Smallest Largest Average
Lapua Ball 2379 7.20 9.60 8.66
(Berdan) 12 Sd

This performance is better than expected of PS Ball in average AKM
and AK47, attributable to better quality of Lapua ammunition.
Note ammunition comparison with SKS above, refiring the same rifle
in Jan., 1988, compared to 1983 results.


U.S. Military Specification Mil-C-70760
Ctg. 7.62x39 mm, Commercial
Dwg. #12598661

Bullet extraction force: 60 lbs. min.
Accuracy: 5.0" max. MR @ 200 yds.
Velocity: 2275 +/- 30 f.p.s. @ 78', Sd 30 max.
(eq. to MV = 2350 f.p.s.)
Chamber pressure: 45,000 psi (Cu) max. avg.
Cyclic Rate: 550-750 r.p.m. in AK-47/AKM rifles.
Bullet Wt. 124 grs., lead core with copper alloy
or gilding metal-clad steel jacket.
Primer: non-corrosive

Penetration Tests of 7.62x39 mm Ammunition by CEH Oct., 1986.
All firings at 50 yds. range against standard CMU ("cinder block")

WEAPON CAL. AMMUNITION TEST RESULTS
AKM 7.62x39mm Yugo M67 Block hit end-on, perforated web,
bullet
lead core broke up and only marked next layer.
Chinese PS Block hit end-on, perf. first and
steel core second webs, cratered third
web, without cracking it.

AR-15 5.56 M193 Block hit end-on, perf, first web
lead core and broke up, marked 2nd next web

M855 Block hit end-on, perf. first and
steel core second webs leaving no damage to 3rd
web other than deposit of debris.
Repeat test of M855 broadside hit
gave complete perforation both
sides of CMU, spraying witness tgt.
3 ft. behind with fragments, steel
core penetrated 3/8" into 1x2 SYP
tgt. frame.

Garand .30-'06 Ball M2 hit end-on perforated first and 2nd
lead core second webs of CMU, heavily cratering
third web, and cracking lengthwise.

TYPICAL DISPERSION OF SELECTED SOVIET AND U.S. RIFLES

Approximate Extreme Spread for 10-Shot Groups, Estimated from
Measured Radial Standard Deviations, (assuming MR as .9xRSd and
ES as 3xMR) NRA Master gunners in favorable conditions adapted
from U.S. Army APG data, AMSAA Technical Report No. 440 , May 1987.

7.62x39 5.45x39 5.56x45 5.56x45
USSR PS USSR PS US M193 US M855
RANGE: AK-47 AK-74 M16A1 M16A2
(metres)
100 4.8 3.5 2.7 2.7
200 9.6 7.0 5.5 5.5
300 14.4 10.5 8.9 8.6
400 19.6 14.9 12.8 11.9
500 25.0 19.6 17.6 16.0
600 30.6 25.5 23.0 20.4

DOCTRINAL
BATTLE-SIGHT
RANGE 300 450 250 300
(metres)
Firing table for 122-gr. Type PS Ball, GMCS mild steel core BT
C7 :.156, Standard Metro, adapted from Soviet and U.S. Army Data
Range Velocity Energy Drop Elev. Max. Hgt.
(yds.) (fps) (ft.-lbs) (ins.) (moa) (ins.)

0 2340 1483 0 0- 1.5
100 2080 1172 3.5 5 0.3
200 1836 913 14.9 8.2 3.5
300 1606 699 37 12.8 9.9
400 1388 522 72.4 18.5 20.9
500 1190 384 126.5 25.6 38.7
600 1051 299 206.9 34.7 65.9

EFFECTS OF TRAINING AND DOCTRINE ON INFANTRY RIFLE EFFECTIVENESS

U.S. doctrine is that the M16 rifle be carried habitually with the
sights set to the BSR unless there is a need to set the sights for
some other range and there is time to do so. American GI's are
taught to aim at the center of mass of the visible target at all
times, which centers the densest portion of the round to round shot
dispersion in the center of the target, to maximize hit
probability. Soviet doctrine is to use a bottom of target point of
aim with the sights set at the BSR at ranges up to 300 metres, and
to set the sights for the estimated range at longer distances. In operational situations the type and magnitude of other system
errors cancel any effect of wind deflection upon hit probability
for the average soldier. The intrinsic single-shot round-to-round
dispersion of the AK47 is larger than the newer AK74, but both
Soviet rifles have a larger intrinsic RRD than either the M16A1 or
M16A2. These differences are not meaningful in most operational
combat situations because stress is the great equalizer. If the
shooter's error approaches the worst hitting performance seen in
peacetime field experiments the differences in being able to hit
an "E" silhouette target caused by differences in inherent weapon
accuracy are wiped out. If effective range is gaged by single-shot
hitting performance of average soldiers in combat situations, the
AK47, AK74, M16A1 and M16A2 have almost no difference in
performance. In US Army testing of the AK-74 rifle it was found
that the time to hit was the same for the AK-74 and M16A1 for
target exposure times of 2-3.5 seconds, but that the
muzzle-break-compensator of the AK-74 was an aid to improving hit
probability at close-range targets with burst fire. The third
round in a burst from the M16 seldom if ever hits anything and is
nothing more than a waste of ammunition. Personnel should be
taught to use two-round "double-taps" for close range engagements
within 50 yds. Beyond 50 yards rapid semiautomatic fire is far
more effective than any type of automatic fire, in being able to
obtain hits, as well as in conserving ammunition.



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