Author Topic: Cast 7.62x39 Load Help  (Read 2325 times)

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ragnar6667

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Cast 7.62x39 Load Help
« on: July 16, 2008, 04:28:57 PM »
I wanted to see if any of you guys pourin' your own x39 bullets using the lee CTL312-160-2R C.E. Harris mold could throw some reload data my way.  I'd like to use reloader #7.  Thanks for any help

handyrandyrc

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Re: Cast 7.62x39 Load Help
« Reply #1 on: July 17, 2008, 12:45:58 AM »
Reloader 7, while optimal for full-power x39 loads, may be a little too slow for running cast boolits WELL.  To get enough Reloader 7 in there to bump pressure enough to make a good seal, you'll be running full speed, which is too fast/high pressure.  You need to go with something a little bit faster to get it to work good.  Funny you should mention Ed Harris' boolit design.  You should check out his load data for the x39 and cast loads as well!  2400 seems to be about the best general powder to use with cast stuff.  You can run it in almost any rifle cartridge with cast.  And you can even get it to cycle in your SKS!

Next post will be the comprehensive C.E. Harris guide to reloading 7.62x39 with cast boolits.

handyrandyrc

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Re: Cast 7.62x39 Load Help
« Reply #2 on: July 17, 2008, 12:46:58 AM »
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 Oil 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 immediately 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 heattreated, 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 fps
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

ragnar6667

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Re: Cast 7.62x39 Load Help
« Reply #3 on: July 17, 2008, 08:19:05 AM »
I was looking everywhere for that article and just could not find it, thanks for your help.  I picked up my first bucket of wheel weights from a tire shop the other day, and I'm really excited to start.

rbstern

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Re: Cast 7.62x39 Load Help
« Reply #4 on: July 19, 2008, 06:22:41 PM »
Randy is the man!  Thanks for the Harris article.  Goldmine of info.
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res45

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Re: Cast 7.62x39 Load Help
« Reply #5 on: July 19, 2008, 08:10:35 PM »
Was posted before but it's been awhile http://www.sksboards.com/smf/index.php?topic=29498.0 lot's of info on this board.