7.62x39 - GB C314-041 - LeveRevolution

[Larry Gibson]

7.62x39 – LeveRevolution Powder

In conjunction with a recent test of Junior1942s favoriteloads for his SKS using the RCBS 30-180-FN (197 gr cast of COWWs) I also tested the 7.62x39 cartridge with theGB C314-041 bullet with LeveRevolution powder.If you read the thread on Junior’s loas you saw that LeveRevolutionpowder under the heavier 197 gr RCBS bullet worked quite well in the 7.62x39cartridge.The RPM Threshold with COWWcast bullets was pushed up 150 + fps while maintaining quite less psi than withthe more popular medium burning powders such as 4895 and Varget.

Referring back to the 30-30 test I conducted withLeveRevolution powder it was found there a bullet of 170 + gr was really neededto get the LeveRevolution powder to burn efficiently.My testing of this powder with cast bulletsso far has consistently shown that LeveRevolution powder requires 26 – 28,000psi to begin burning efficiently.Withthe 30-180-FN seated to max magazine length for the SKS 27.5 gr gave about 105%load density and produced 28,700 psi(M43) under the RCBS 197 gr bullet and gavevery good accuracy at 1843 fps out of the test rifles 20” barrel.

The question was; would the 175 gr (COWWs + 2% tin at 13 –15 BHN) GB C314-041 provide enough mass for LeveRevolution to burn efficiently?With the bullet seated so the cartridge OALwas 2.206” the load density of LeveRevolution powder at 100% was 29.5 gr in theFL sized Winchester cases.I ran an initialpressure/velocity work up from 26.5 gr to 29.5 gr.That showed the 29.5 gr load might be 25,000psi at around 1900+ fps.I loaded 10shot test strings of 27.5, 28.5 and 29.5 gr to test.

Results;

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

Testequipment; Oehler M43 PBL

Range;Sara Park, Lake Havasu City, AZ

Testrange; 100 yards, solid cement benches

[FONT="Times New Roman"][SIZE=3][COLOR=#000000][FONT=Calibri]Rest;Hoppe’s front and leather sand bag (rabbit ear) rear

Attachment 150923


Bullet; Lee Group buy 6 cavity C314-041

GCs; mine out of .014 brass shim stock

Lube; NRA 50/50

Sized to; .312

Alloy; COWWs + 2%tin AC’d BHN 13 – 15



Cases; Winchester, FL sized



Primers; CCI 200



Cartridge OAL ; 2.206” with GCs at the bottom of the caseneck with light crimp under driving band.



The 27.5 gr load; we see this load did not burnefficiently at all. The cases were sooty clear back the case head and aroundthe rims.The large ES of velocity andgroup size of 5.5’ says it all.I tracethrough the target bullet holes onto the data sheet for a record of the group.





Velocity; 1781 fps

Psi(M43); 22,000

Accuracy; 5.5”
[FONT=Times New Roman][SIZE=3][COLOR=#000000]

Attachment 150927


28.5 gr; Accuracy got better and the ES was about half ofthe previous load.This indicates thepowder is starting to burn more efficiently except there still was soot abouthalf way back along the cases indicating the pressure curve was not sufficientfor the case to obdurate and seal the chamber.



Velocity;1884 fps

Psi(M43);23,900

Accuracy;3.6”
[FONT=Times New Roman][SIZE=3][COLOR=#000000]

Attachment 150928


29.5 gr; things are beginning to come together.The psi is still a bit low as we see a coupleof the shots fell out the bottom psi wise.The velocity ES is very good and the accuracy given the velocity is alsoquite good.Still some sooting of thenecks and shoulder area on the cases indicating obturation of the case is stilla problem.The average psi is stillbelow where LeveRevolution really burns efficiently.



Velocity;1944 fps

Psi(M43);24,800

Accuracy;2.5”
[FONT=Times New Roman][SIZE=3][COLOR=#000000]

Attachment 150929


Perhaps in the test rifle which is a bolt action necksized fire formed cases will allow 30 gr or maybe 30.5 gr of LeveRevolutionpowder with this 175 gr bullet in the small 7.62x39 case.If so then the psi may get high enough forefficient powder burning.However, forthose who might want to use this powder in the SKS or AK I suggest a heavierbullet of 180 at least and perhaps 185 gr or use the RCBS 30-180-FN which seemsto cast on the heavier side.



Larry Gibson

[Larry Gibson]

Just checked and if I seat that bullet out to 2.238 oal the GC is just at the base of the neck and I can roll crimp under the middle drive band. The front drive band just kisses the leade. Case capacity of the R-P fire formed cases is 31.5 gr of LeveRevolution so I guess I've another test! The 1944 fps load is pushing 147,300 RPM so it will be interesting to see if I can push the RPM threshold higher with this bullet cast of COWWs + 2% tin and AC'd. Worth a try.

Larry Gibson

[Loudenboomer]

Thanks for the write up Larry. The seemingly small window of usefulness of LeveRevolution just got Bigger!

[silverado]

You are awesome.... thanks... I really want get an x39 now... jerk.... (that last part is from my wife)

[Artful]

- thank you

[NYBushBro]

- thank you

+1... Touche!

PS: I plan on using the Saeco #305 (.311 version of their 30-30 bullet) and WD the projectiles.

[GREENCOUNTYPETE]

thankyou very much for the data

[nekshot]

again Larry thanks, I do kinda envy your little rifle but I'll shoot my carcano and dream of the little mausers! I do know this cartridge is a fun deal in cast, maybe because in Jacket version its not a real earth shattering cartridge!

[NYBushBro]

NOTE: the original load for the 30 WCF was a 160 gr bullet @ ~1950 fps. If we can reproduce this with the 7.62x39 cartridge, it will be '30-30 spec'... albeit 1895 specs.

(Of course, heavier is better... at the same velocity.)
The SKS barrel twist is definitely the 'kicker', in this case.

Hope reigns eternal...

[30hrrtt]

Larry, did you ever shoot this load with 31.5 grains and if so, what was the psi? How did it do? Thanks.

[BNE]

Mr. Gibson, your data and documentation is great. Thanks. Lever Revolution is one of the few powders I always see available here. I have not tried it yet.

[VintageRifle]

Hello,

Has anyone else given leverevolution a try in their sks with heavier bullets? I have a lb of this powder that I was going to try out, but it looks like there hasn't been much of a interest and/or reporting on results past Larry Gibson's reports.

Thanks,
Nick

[nekshot]

Hello,

Has anyone else given leverevolution a try in their sks with heavier bullets? I have a lb of this powder that I was going to try out, but it looks like there hasn't been much of a interest and/or reporting on results past Larry Gibson's reports.

Thanks,



Nick

I only use lvr in this cartridge and 30-30's anymore. It simply is too good of a powder to mess with the other stuff. I shoot heavy boolits so it is perfect for me. If i was a plinker there are much better powders.

[rollmyown]

Thanks for the write up Larry. I can't view the attachments, is anyone else having any trouble?

[Bloodman14]

I've been experimenting with NOE's 316299 and Tom's (Accurate Molds) 316215B with LeveRevolution; 1.4 to 1.6 cc's give good accuracy, function just fine, and fit the Tapco SKS magazine. I will post more when I have time; I have been working 10 to 15 day stretches for the past few months!

[Larry Gibson]

I re-added the attachments to the original post.

I also continued the test with a redo of 29.5 gr LvR and then tested 30, 30.5 and 31 gr LvR under the same 170 gr cast bullet. All loads hovered right at 2 moa for 10 shots. The 31 gr load was 100% load density It was right at 2 moa ay 2076 fps out of the 20" Mini Mk X. The psi MAP was 32,400 psi(M43) so all was well, very well indeed. That load pretty much does duplicate the "standard" 30-30 load with the same bullet out of a 20" M94 or M336 Carbine.

Larry Gibson

[NYBushBro]

What is the barrel twist in your Mini Mk X?

Thanks for the additional testing; I think that Junior would be smiling at that 31 gr load of LVR.

[Larry Gibson]

The Mini Mk X 7.62x39 has a 9 1/2" twist.

Larry Gibson

[30hrrtt]

Thanks Larry. Time to mess around a little.