CE Harris Quesiton on SKS Loads

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  • Last Post 08 November 2011
kokojoe posted this 17 December 2009

I've been working with CE Harris two articles on “CAST BULLET LOADS FOR MILITARY RIFLES” and a post he did specifically for the 7.63x39.

I'm using the Lee C312-155-2R.  I use 50/50 lube and run it through a .313 sizer mostly to lube and install the Horanday gas checks - the bullets don't usually get sized much.

I've got my Norinco SKS working great.  I started to get it to cycle at just over 12.5 grains of Alliant 2400 and seemed to work better as I approached just under 14.  So, I loaded up a supply at 14.5 since I'd be doing some cold weather shooting as well. 

I just got a Yugo SKS.  The 14.5 won't cycle it - they don't even stovepipe.  The action opens just a bit.  This load chronys at just about 1,700.  The Wolfe 122 grain FMJ works this action fine and chronys at about 2350+.

In one article Harris suggests that the max load of 2400 in the 762x39 case should be 16.  Then, he had an update to a post in 2008 suggesting not to exceed 15.  I doubt that 15 will do it for me - and I'm not sure even 16 will work.

His addition to the one post says:

"Most up to date info from Ed Harris - 2008 Quote: In the SKS start with 11 grs. of #2400 and increase the load gradually until you get reliable function. Do not exceed 15 grains of #2400. You can work similarly within the range of 13-18 grs. of 4227, 16-22 grs. of 4198, 18-24 grs. of RL-7"

So, my quesitons start off here:

Should I limit the 2400 to 15 grains - in which case I should rule this out for this gun.  Or should I try it up to 16 - in that case I'm skeptical but it might just work.

Then, assuming the 2400 wont work - would some of the other powders he suggests here such as 4227, 4198, or RL-7 make a difference?  Of them all, I'd like to try the RL-7 first.  Do I just start at the lowest charge knowing that the max of 2400 does not work - or could I start at mid-range charges?

If I were to get to whatever the max is on 2400, I'm trying to understand why another powder would work without also being over maximum.

Thanks

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RicinYakima posted this 17 December 2009

The chemical composition of Alliant 2400 has been changed since Ed's original work with that powder. It is slightly faster and reaches peak pressure sooner than the old Hercules formula. So, I would go with Ed's updated recommendation.

A group of friends and I bought a bunch of the Yugo's when they were first imported. They are much tighter than any of the others. It took about 100 rounds of Silver Bear ball before they were reliable. I shoot cast bullets from a 7.62X39 Springfield, so don't have a load for the SKS. However, I would work with IMR 4227 next if I were in your shoes.

HTH, Ric

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kokojoe posted this 20 December 2009

Ok, here's what happened with the RL7.  I loaded 3 cartridges each with 18, 19, 20, 20.8, and 22.  Right off the bat the Yugo cycled fine with the lowest load.  There were no signs of overpressure on any.

Used Fiocchi cases and Winchester LR primers.  Lee C312-155-2R, put through the 313 Lyman die for lube and gas check. Die did not size the bullet so probably shot as cast.  Also double lubed with LLA.  Air cooled WW approx 12 BHN.

Conditions 35 degrees, cloudy.  Chrony approx. 10' from muzzle.

Here's the Chrony info:

18.0 grains: 2 valid readings, Avg. 1,559 FPS, 72 ES, 59.91 SD.

19.0 grains: 3 valid readings, Avg. 1,610 FPS, 142 ES, 70.76 SD.

20.0 grains: 3 valid readings, Avg. 1,859 FPS, 34 ES, 18.35 SD.

20.8 grains: 1 valid reading @ 1,838 FPS.

22.0 grains: 1 valid reading @ 1,926 FPS.

So, at least I know they all cycle the Yugo where near the maximum of 2400 would barely move the action.  Now I'll need to work on these to develop a standard load that works well for both the Yugo and Norinco.

So, the RL7 must be slightly slower than the 2400 and maybe building better or more sustained pressure to cycle the action?

Any thoughts as to what load would be best to focus on?

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RicinYakima posted this 20 December 2009

RL7 is a lot slower than 2400. That the pressure is higher at the gas port, where neeeded for function the action, with RL7, regardless of what the maximum pressure of the load is in comparison. While I am not a true believer that small ES and SD relate that well to accuracy at less than 200 yards, I'd work in the 19 thru 22 grain area looking for accuracy. The rifle will tell you what it likes.

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res45 posted this 21 January 2010

I've been working on some cast bullets loads for my SKS rifles for a couple weeks using the Lee .312 160 gr.tumble lube gas check bullet.  I finally settled on 12.5 grs. of Alliant 2400 the MAX load in the 7.62 x 39 case would be 15.0 grs.  This load is very accurate in both my Chinese and Yugo SKS producing similar groups,no leading and cycles both rifles dropping the brass about 5' from my shooting position.  I also want to mention I did a ladder test in .5 gr. increments and the 12.5 and 14.0 gr. loads shot equal size groups,the main difference is the 14.0 gr. load felt and ejected  brass in the same manner as the 123 gr. ball ammo.

My Yugo shoots flatter than my standard Chinese SKS a rear sight leaf adjustment of 400 meters was required to hit the same point of aim with the cast bullet as the factory 123 gr. ball would at a 100 meter rear sight setting.  I used the same 400 meter setting on the Yugo and it shot high by several inches as the target shows so 200 or 300 meter setting is probably going to be more appropriate for the Yugo SKS.

The TL GC bullets were cast from straight WW alloy and water quenched,lubed once with Lee Alox that has been thinned with mineral spirits 1 oz. to the 4 oz, bottle of Alox and allowed to dry overnight,gas checks were then seated with a Lee .314 sizing die with no sizing applied to the bullet.  Then TL once more and allow to dry before loading.  I use the Lee FCD on the posted target,I seated the bullet right to the edge of the crimp grooves and used a med crimp,I'm questioning if I should be using the FCD or a roll crimp on this type bullet,I have lots of experience  using the FCD's on various ammo and not being overzealous with the crimp especially on lead bullets.  I just want to produce good accurate ammo,what type of crimp i use to get there is not important.

5 shots 50 yds. Chinese & Yugo SKS

'Artisan' in Lead, Brass & Powder.

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Ed Harris posted this 21 January 2010

If your group shown is typical I would change nothing!

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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res45 posted this 21 January 2010

Thank You Mr. Harris for the reply,one question I had since I haven't seen much data on is.  When using the Alliant 2400 powder whats  the general muzzle velocity range I would be looking at using 12 grs. min. and 15 grs. max. in the standard length SKS.

Hopefully in a couple week if the weather is decent I can run my test loads through my friend chrono,just wondering if you had a good estimate or anyone else on the board had chronographed  a similar load.

'Artisan' in Lead, Brass & Powder.

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SteveR_1 posted this 09 February 2010

Hi,

Just a thought, change out the springs from the one that cycles with the 2400 load, to the Yugo, and see if that makes a difference. You may just need to get a reduced power spring for the Yugo. I have had cycling problems with one of my Romanian SKS's and changed out the recoil spring, and worked great.

Steve

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Ed Harris posted this 09 February 2010

With #2400 and C312-155-2R the 12-gr. load will be about 1300 f.p.s. and the 15 grain load about 1800.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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kokojoe posted this 09 February 2010

SteveR_1 wrote: Hi,

Just a thought, change out the springs from the one that cycles with the 2400 load, to the Yugo, and see if that makes a difference. You may just need to get a reduced power spring for the Yugo. I have had cycling problems with one of my Romanian SKS's and changed out the recoil spring, and worked great.

Steve

Good idea - I will definately try that.  If it works, what is the best source for springs and how do you know what strength you are getting?

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res45 posted this 09 February 2010

It's possible you may have a slight gas leak on the Yugo,you can fashion a gasket from a paper clip that fits around the nipple on the gas valve to tighten up the seal between the valve and tube. 

That may give you better cycling,I installed a new valve in my Yugo right after I purchased it and it's cycled just fine ever since.

'Artisan' in Lead, Brass & Powder.

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SteveR_1 posted this 09 February 2010

I can't remember where I got the spring, I bought the spring and some spare firing pins about 2 years ago. I may have gotten the spring from a buddy of mine. I used this place in the past, no problems:

http://www.sarcoinc.com/sks.html

I want to say the US made springs were lighter, but it did help my Romanian SKS.

Steve

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Buzzard Bill posted this 08 November 2011

You are right on Joe with the Yugo SKS, I could not get mine to function useing 2400 with a 150 gr. cast bullet. I loaded your RX7 loads and they all functioned fine. 19 grs. seems to be the most accurate so far, 4” group at 100'.

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