Junior1942's 7.62x39 SKS loads + with LeveRevolution

[Larry Gibson]

Junior1942’s7.62x39 loads

During the latest thread on LeveRevolution Powder Junior1942 PM’d me asking about the 30-30 testing I had done with the RCBS 30-180-FN and that powder.He asked about the test and was trying to correlate the psi’s from that test to the 7.62x39 for possible use in his YugoSKS.He primarily was interested to see if the LeveRevolution powder would give him a bit better performance under his COWW cast bullets which weight 197 gr.Isuggested there was no sense trying to correlate when I could pressure test in the 7.62x39 also.I suggested he send some bullets and the data for his other powder loads and I would pressure test those also.Junior thought that was agreat idea.He asked how many bullets?I told him a hundred minimum.

Junior scrounged around and found about a hundred (104 to be exact) he had already cast and said he’d cast up some more and send ’em if need be.He said a few were wrinkled.Told him they’d be fine for the initial LeveRevolution work up as we were interested there was the psi. I got the bullets a couple days later.They were sized at .314, had Hornady GCs and were lubed with LLA.The BHN measured 11 – 12.I proceeded to check out the Mini Mk X Mauser I would use for the test.Unfortunately the strain gauge had partially cracked for some reason.It hadn’t been used in over 2 years and the change in location, temperatures and humidity are my guess why.Called the company to order some more gauges and they would take about 6 – 7 weeks.Told Junior and he was a bit down over that.However, in about 2 weeks a package showed upwith the strain gauges.

IPM’d Junior and told him I was ready to test and asked a couple clarification questions about his standard loads.I didn’t hear back from Junior and just assumed he was away or busy.I did not know he had gone to the big range.I proceeded with the test and will post the results here…..for Junior…..rest in peace, may the sun always be to your back, the wind in your face and all your shots fly true.

Test rifle; Interarms Mini Mk X
Caliber; 7.63x39
Bore; .301
Groove; .311
Barrel length/twist; 20”/1-9.5”
Sights; Bushnell 4X scope

Testequipment; Oehler M43 PBL

Range; Sara Park, Lake Havasu City, AZ

Test range; 100 yards, solid cement benches

Rest; Hoppe’s front and leather sand bag (rabbit ear) rear

Test shots; due to limited number of bullets not all test strings had 10 shots. Some had less but not less than 7 shots.The LeveRevolution psi workup had 2 shots per powder charge.

Attachment 112982


The test was conducted on two separate days early in the mornings. This gave the least heat (this is the desert with day time temps running 105 – 115) at daybreak (85 – 90) and the least wind. Juniors standard loads and the LeveRevolution psi work up was conducted on the 1st day along with a LeveRevolution psi workup with a 175 gr C314041 cast bullet of my own. The second day was the test of 3 loads of the LeveRevolution under Juniors 30-180-FNs and 3 loads under my own C314041.

The 1st day’s tests;

Reference ammunition test; The CIP Pmap (Maximum Average Pressure) for the 7.62x39 cartridge is 51,500 psi (peizo-transducer or strain gauge. Three factory loads were tested to set a base line for the mini Mk X.

Attachment 112983

[Larry Gibson]

WolfFactory FMJ
Velocity;2498 fps
Psi(M43);46,400
Accuracy;5.4”

The pressure trace for this load was also graphed out to calculate the approximate psi at the gas port of a SKS.The gasport was measured at 13.4” from the bolt.Gas port psi with this load was approximately 13,200 psi.

Attachment 112984

Herter’s Factory FMJ
Velocity; 2549 fps
Psi(M43); 46,100
Accuracy; 3.3

Wolf Factory HP
Velocity; 2581 fps
Psi(M43); 46,700

Cases; IMI 7.62x39
Primers; CCI 200
Bullet; RCBS 30-180-FN (197 gr)
Cartridge OAL; 2.24 (fit the test rifle magazine and my Russian SKS and fed fine from both) which put the top of the GC right at the case neck.
Crimp; Roll under the 3^rd drive band

Attachment 112985


Junior used 3 different powders for his standard loads; Varget, H4198 and surplus 4895.He sent 3 loads for the Varget and 4895 to test and 2 for the H4198.



Varget loads;Junior sent 3 test loads for Varget powder; 23.3 gr, 24.7 gr and 26 gr.Junior stated the 26 gr load was compressed and it was.



23.3gr;

Velocity; 1608 fps

Psi(M43); 27,200

Accuracy; 2.1” (7 shots)

24.7gr;

Velocity; 1700 fps

Psi(M43); 30,300

Accuracy 1.78 (8 shots)



26gr;

Velocity; 1778 fps

Psi(M43); 35,100

Accuracy; 4” (8 Shots)



We see here the RPM Threshold of these components is between 1700 fps and 1778fps.Accuracy went from very good at 1700 fps and 128,800 RPM to poor at 1778 fps and 134,700 RPM.



Junior specified two loads for H4198 powder; 21.3 gr and 22.7 gr.



21.3gr;

Velocity; 1820 fps

Psi(M43); 42,200

Accuracy; 4.9” (8 shots)



22.7gr;

Velocity; 1925 fps

Psi(M43); 50,700

Accuracy; 7.5” (8 shots)



With these two loads of H4198 we see higher psi’s and velocities and poor accuracy.Both loads exceeded the RPM Threshold for these components.The RPM was 137,900 and 145,900.The 22.7 gr load also came very close to the CIP Pmap.



Junior specified three loads of surplus 4895; 23.4 gr, 24.5 gr and 24.7 gr.Hard to say how close our different lots of4895.I have two lots and used the one that is closest to IMR4895 in burning rate.



23.4gr;

Velocity; 1706 fps

Psi(M43); 32,300

Accuracy; 3.3 (8 shots)

Note; comparing the accuracy with the Varget 24.7 gr load we see the Varget load is more accurate at very close to the same velocity.Note however, the Varget load has the lower psi meaning the time/pressure curve was slower.We see that in the pressure traces and in the “Rise” data.The 4895 load reached pressure in 129 microseconds while the Varget load took 144 microseconds.Seemingly not much of a difference but when pushing the RPM Threshold the devil is in the details. Top trace is the 4895.

Attachment 112986



24.5gr;
Velocity; 1767 fps
Psi(M43); 35,200
Accuracy; 4.8” (8 shots)

24.7gr;
Velocity; 1778 fps
Psi(M43); 35,800
Accuracy; 4.5” (8 shots)

Junior’s chronographed velocities were about 80 fps less than the ones I recorded. The velocities I list are corrected to the muzzle and differet rifles were used of different actions. Additionally the lot to lot variation of the powder used and I was testing in 85 – 90+ degree temps all combine for the differences. For what Junior was looking for (a “smack down” hog load for 100 yards or less) his Varget or 4895 loads would have been fine.

[Larry Gibson]

LeveRevolution Powder with the 30-180-FN at 197 gr in the 7.62x39

I did a “workup test” using LeveRevolution powder. What I do is usually load 2 cartridges (sometimes just one) of increments from a start to a projected “max” load. I used to call this “ladder testing for velocity and psi” but too many confused this with the “ladder test” now commonly used for working up loads. What I do does not consider accuracy at all. My testing is concerned with velocity and psi.

With LeveRevolution powder I worked up from 23.5 gr to 28.5 gr in 1 grincrements. 28.5 gr was at 105% load density with the RCBS bullet. Velocities ran from 1554 fps to 1924 fps with psi’s from 20,100 to 36,300. Knowing the RPM threshold was between 1700 fps and 1750 fps with the other powders I loaded 25, 26.5 and 27.5 gr looking for velocities from the mid 1600s to the mid 1800 fps. The idea was to see how far the much slower burning LeveRevolution with its radically different time/pressure curve would push up the RPM Threshold.

25gr;
Velocity; 1668 fps
Psi(M43); 22,400
Accuracy; 6” (7 shots)and very poor.There was soot blown back the the expansion ring on the cases indicating poor breech sealing.

26.5gr;
Velocity; 1771 fps
Psi(M43); 26,500
Accuracy; 2.4” (9 shots) no sooting on cases. Accuracy definitely improved.

27.5gr;
Velocity; 1843 fps
Psi(M43); 28,700
Accuracy; 2.65” (9 shots) definitely pushed the RPM Threshold up as RPM is 139,700. 28.7gr is worth a try but alas I am out of the RCBS 30-180-FN bullets………note on the data sheet the group is marked. The 1^st and 2^nd shots and they were right at the bottom of the target I was using. To make sure I didn’t lose any shots off target I moved the scope elevation up 3 moa and finished the test.Those 1^st two shots would have been in the group.

Attachment 112987


This definitely should be the better “smack down” load in the SKS that Junior wanted. Graphing out the psi at the gasport shows a projected 8000 psi which is less than with the different Russian made factory 7.62x39 ammunition. I would have tested this load in my own SKS but again, I am out of the bullets! Perhaps Junior is hunting with this load already! I sure hope so……and I’m sure he wouldn’t mind me sharing with all of you. That’s the kind of guy Junior was. He loved to share here and on his own website. I will miss Junior……….



LarryGibson

[3006guns]

Wow Larry.........some pretty intensive and enlightening work! I came across Junior's 7.62 x 39/4895 load a couple of years ago and have been tickled to death with it ever since. My loads pretty much reflect the velocities and now I have an idea of the pressures involved. Thank you!

[JeffG]

Larry,

Thanks a bunch, very educational. The cutaway of the cartridge showing how deep the base of the bullet was into the case was very useful for me.

[nekshot]

thanks a ton Larry now I can proceed with my rifle with confidence rather than hoping for the best, and yes may Junior trully rest in peace.

[GhostHawk]

It was another thread where Junior pointed the way with a couple of powders that would work well. I ended up going the 4895 as it was what I could get. I'm using a slightly different but similar 185 grain that with gas check and lube comes closer to 195gr.

I don't have a chrony, but with the 22 gr loads the Yugo SKS came alive sending them exactly where I pointed with good speed and no faults.

Thanks Junior, thanks again to Larry.

I suspect Junior is someplace watching all of those seeds of knowledge that he planted sprout, grow and bear fruit.

[cpileri]

great info!

[NYBushBro]

27.5gr;
Velocity; 1843 fps
Psi(M43); 28,700
Accuracy; 2.65” (9 shots) definitely pushed the RPM Threshold up as RPM is 139,700. 28.7gr is worth a try but alas I am out of the RCBS 30-180-FN bullets………note on the data sheet the group is marked.

Larry - thanks for your time and effort on this one.

If you would like to try that 28.7 gr load of LVR with the NOE 311-180 FN, I could cast up some and mail them to you.

I corresponded with Junior during the GB for the NOE mold, and bought one also, so I'm guessing (hoping?) that they should be dimensionally similar.

Let me know how many you would need to finish up this test with your SKS, and i will try to get them to you ASAP. Send me a PM if you are agreeable to this.

PS: I keep thinking that WDWW might be time better spent than trying to 'push the envelope' with ACWW (which I am surmising Junior's bullets were, just from the BHN numbers.)

Glad to hear that the port pressure (at least so far) is not 'over the top' for SKS carbines.

I think Junior would be pleased at this thread... I know I'M glad you did these tests.

[Larry Gibson]

NYBushBro

Sounds like a plan to me....I'll PM the details.

Note the new thread with the 175 gr bullet. It was cast with COWWs + 2% tin and best accuracy was at 1944 fps so the slower powder is definitely doing some good pushing up the RPM Threshold. Be interesting to see what those 180 NOE's do, especially if they are harder and heavier than 180 gr?

Junior wanted to use straight COWWs as that's what he'd been talking on his site. His interest was close range pigs at 100 yards or under so a 4 - 5 moa load was fine. He didn't want to chance the bullets being too hard and shattering. Was fun doing the tests and I'm sure Junior appreciates the interest ya'll are showing.

Larry Gibson

[JeffinNZ]

Thanks Larry. Great to see gas port pressure. Very hard to find that sort of info.

RIP Junior.

[MBTcustom]

Well done Larry. Excellent data!

[Love Life]

Thank you for your time and effort in doing the testing and posting this.

[NYBushBro]

Boolits are on the way!

[30hrrtt]

I don't have the 7.62x39 but do have a 30 Herrett 1 in 10 twist I play with a lot. It is almost identical to the 7.62x39 round in capacity. I have the 30-180-fn and a lee 170 that casts at 180 grains with my alloy that I haven't tried yet. I think I will be playing with both these boolits and varget, 4895, and LeveRevolution. Your pressure numbers are very helpful in both this post and the other post. My barrel is 10" and think the 4895 will be the best performing of the listed powders.

This isn't the military round specified but would appreciate any thoughts. Or we could keep it to a short barrel 7.62x39, like about 10"

[Larry Gibson]

I don't have the 7.62x39 but do have a 30 Herrett 1 in 10 twist I play with a lot. It is almost identical to the 7.62x39 round in capacity. I have the 30-180-fn and a lee 170 that casts at 180 grains with my alloy that I haven't tried yet. I think I will be playing with both these boolits and varget, 4895, and LeveRevolution. Your pressure numbers are very helpful in both this post and the other post. My barrel is 10" and think the 4895 will be the best performing of the listed powders.

This isn't the military round specified but would appreciate any thoughts. Or we could keep it to a short barrel 7.62x39, like about 10"

If we look at the time/pressure curves there is going to be very high psi at the muzzle, especially with the LeveRevolution powder. Muzzle blast might be ferocious! Only one way to know.......let us know how it works in those short barrels.

Larry Gibson

[Larry Gibson]

Boolits are on the way!

Got 'em today, look good, will size, lube, GC and load tonight. Got some of my GB C314-041s cast also to do same with. Hopefully thunderstorms and wind will cooperate this week for a test(?).

Larry Gibson

[Larry Gibson]

Ran the test this morning. NYBushBro's NOE 30-185-FNs ran 203.7 gr with a very soft BHN of 10. That showed in the group size. I loaded them over 27.5 gr LvR powder (100% load density). Out of the Mini MK X they ran 1880 fps with very good internal ballistics as evidenced by the data and time/pressure curves. Accuracy left a bit to be desired with 8 shots going into 2.7" and 2 flyers stretching it out to 5.5" at 100 yards. I attribute that to the very soft alloy as a BHN 10 just doesn't cut it at 1880 fps.

I then fired 10 shots through my Russian SKS. The gas tube has been vented to curtail the violent ejection of milspec ammo. Functioning was actually a bit milder with this load. I would not hesitate to use this load with LvR powder in my SKS for hunting. I would however harden up the alloy to at least 14 - 15 BHN. Using a better ternary alloy would likely drop the bullet weight closer to 185 - 190 gr, increase velocity and probably improve accuracy.

Larry Gibson

Attachment 114933

[Larry Gibson]

I also further tested the C314-041 in the 7.62x39 with increased loads of LvR powder. I loaded 29.5, 30, 30.5 and 31 gr. The 31 gr load was slightly compressed and it did not show much improvement over the 30.5 gr load which was 100% load density. Accuracy remained fairly consistent at around 2" groups for the 10 shots at 100 yards. That's about what this little rifle is capable of with heavier bullet loads. I can't complain and will probably use the 30.5 gr load with the GC C314-041 bullet as the "standard" load now. At 2069 fps out of this little rifle it really does equal factory 30-30 loads.

Larry Gibson

Attachment 114934

[izzyjoe]

Thanks for taking the time working up those loads Larry, I didn't know Junior had past, I really liked him, and enjoyed talking with him. he seemed like a Good 'Ol boy! RIP Junior, enjoy those happy hunting grounds, 'ol mossy horns is waitin' for you!