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.

               Vel.@15'   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. 
               Vel.@15'  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. 

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                