Date: 27 Mar 94  10:27:05
From: Ed Harris
To:   Bob Horn
Subj: Re: sks reloading

In a message of <Mar 23 17:49>, Bob Horn (1:124/2107) writes: 

 > I recently acquired an sks...I would like to see more on cast bullets.

 BH>Ed (or Bob, if you're looking), looks like it may be about time for a
 BH>"Practical Dope" repost.

PRACTICAL DOPE ON THE 7.62x39

By C.E. Harris - UPDATED 3-27-94

I have reloaded thousands of rounds of 7.62X39 ammunition with
both cast bullets and jacketed, in the AK and the SKS.  I got
frustrated with the AK as accuracy of these seems is generally
poor, at best about 5-6" at 100 yards.  The SKS is more
reasonable, about 3-4" and is still a real bargain these days. 
Most SKS rifles group better with cast bullets than they do with
ball ammunition.   If you are new to cast bullet shooting or not
inclined to do a lot of experimenting, I recommend 14.5-15.5 grs.
of Hercules #2400 with the Lee .312-155-2R bullet, cast of wheel
weights and sized .312".  With this load the rifle functions like
the proverbial pony trotting, and dumps the cases right at your
feet!  You can also try 18-21 grs. of 4198 or 16-18 grs. of 4227
with any bullet from 122-125 grs.  

The gas ports on these guns are larger than they need to be for
reliable functioning.  Lead fouling of the gas port is not a
problem, but the gas piston and cylinder will foul, which can
affect functioning if neglected. The gas piston should be removed
and cleaned with Break Free, Marvel Mystery Oiil or Dexron IIe ATF
and 000 steel wool after each use, and the gas cylinder scrubbed
with a shotgun bore brush.  Liberally lubricating with Break Free,
Marvel Mystery Oil or Dexron prior to reassembly eases the fouling
problem. You can fire several hundred rounds between cleanings
if you avoid super heating the rifle with rapid fire so that
the barrel becomes too hot to hold in the bare hand.  If you do so, 
and let the rifle cool without stripping and cleaning it immediatel
it WILL be difficult to disassemble! 

I have not found lead fouling to be a problem in ordinary
National Match Course style firing, but only in factory endurance
tests of the Ruger Mini Thirty when I was at Ruger.

Ruger does not recommend handloads of any type.  Therefore,
they don't recommend cast bullets at all.  However, in my experience
cast loads about 1 grain heavier than the minimum which cycle an SKS
or AK will work in the Ruger.  These pose no real functional 
problem as long as the gas piston and its recess in the slide handle
are kept clean and well lubricated.
  
The only common cast bullet designs which are correct for the my 
original NEI designs for this caliber and the Lee .312-155-2R
and TL.312-160-2R.  The latter two are adaptations of my original 
NEI design with minor changes to suit Lee's manufacturing process,
and to change the appearance slightly so the Lee version would have
a distinct "product identity."  Now that NEI is back in business (51583 
Columbia River Hwy., Scappoose, OR 97056) Walt Melander can provide my
original 52A design with its 1-1/2-degree tapered forepart or
a stepped-diameter design similar to Lee's adaption, but with a
blunter nose shape which is better for hunting.  Accuracy-wise 
there is no difference between them.

I designed these bullets with the intent to have the heaviest
bullet which could be loaded 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.

Use of a heavier bullet is also better suited for the typical
10-inch twist rates of 7.62x39 barrels. These bullets have only one
grease groove, (which is enough) and a substantial crimp groove .26"
from the base.  The rear driving band casts .312", the front band
.310" and the forepart ahead of the crimp groove is .308."  The ogival
radius starts from this point in order to maximize bearing length.

These bullets have proven very accurate in a variety of military
rifles for target work at up to 200 yards.  They out shoots ball ammo
in the SKS or AK with any reasonable load.  In a bolt- action target
rifle they are capable of 1-1/4" 10-shot groups at 100 yards, and in
a 2-groove 03A3 Springfield or M1917 Enfield they average around 2 moa
ten-shot groups at 200 yards with iron sights, with refined loads.

I use 1 part of linotype to five parts of wheel weight metal for
competition in my .30-'06 M1917 Enfield and M1903 Springfields up
to 200 yards with 16 grs. of #2400, 20 grs. of 4227, 13 grs. of 
Red Dot or 12 grs. of 700-X.  Accuracy of these light cast bullet
loads is far better than Ball M2 service ammunition.  I use
the same charges in the .303 British and  7.62x54R Russian as
well.  I fill the grease grooves with 50-50 Alox beeswax (Lee
brand) then tumble Lee Liquid Alox on for a light golden
overcoat.  These loads don't lead for continuous use over the
National Match Course, even over double-strings of rapid-fire. 

Above 1800 f.p.s. I use the same alloy, but cast the bullets
"hot" until they are uniformly frosted, then quench them directly
from the mould.  The heat-treated, double-lubed bullets will
stand 2000 fps. in wheelweight alloy without leading, if shot
straight from the mould without sizing, being GC'ed in a .313"
die.  A caseful (28 grs.) of Accurate 2230, 2460, or H335 gives
around 2000 f.p.s. in the 7.62x39. 

Accurate Arms 1680 is very similar to the Olin 680 Ball powder,
though slightly slower.  Both of these powders are used in
7.62x39 ball ammunition, with a charge of 24 grs. being correct
for service velocities with 123-gr. jacketed bullets using the
Accurate-IMI propellant, and 23 grs. for the slightly faster Olin
powder.  For a full-power load approximating service ammunition
you can also use 26.5 grs. of RL-7 or 25.0 grs. of IMR or H4198.

With cast bullets the minimum load with 1680 which functions the
SKS with the Lee .312-155-2R is 16 grs.  In the SKS this produces 
about 1420 f.p.s. and 3"  groups at 100 yds.; 18 grs. gives 1630
f.p.s. and 4" groups in the SKS.  I did two strings with the Olin
680 for comparison with the NEI 155-gr. cast bullet at 18 and 19
grs., respectively, which gave 1810 and 1930 f.p.s. I would not
exceed 19 grs. of Olin 680, or 20 grs. of Accurate 1680 with the
155-gr. cast bullet, as these are both full loads.  

The following tables provide additional test data on the 7.62x39.

Jacketed bullet handloads for 7.62x39- Lapua cases, Fed. 210
primers, Ctg. OAL 2.19" from CEH article in Handloader's Digest
12th. Edition, 1990, p.125.

               20" P/V on Univ. Receiver.         Vel. 24" Sako 

123-gr. FMJ    24.5 H4198     2264 fps. 48,170 cup     2377
               26.5 RL-7      2325 fps  52,000 cup     2451
               28.0 H322      2180 fps  42,300 cup     2287
150-gr. SP     28.5 BLC2      2030 fps  40,000 cup     2140
               23.0 RL-7      2050 fps  52,000 cup     2162

Accurate Arms 4th Edition for 7.62x39, SKS with 20.5" barrel
               START                    MAXIMUM
123-gr. FMJ    24.0 A1680 2233 fps      26.5 A1680 2350 fps
               26.5 A2230 1840          29.5 A2230 2086 fps

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



In Home Mix We Trust, Regards, Ed
 

--- msged 2.05
 * Origin: Home of Ed's Red (1:109/120.3006)

