Replicating 7.62x39 ballistics

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Gryphon Energetics

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I think I may have posted something similar many months ago, but here goes again.

We need something that can provide 7.62x39 ballistics at up to 200 meters with sub-MOA accuracy. We've tried a number of different platforms in that caliber and have not come away satisfied with any of them. We do not necessarily need to shoot 7.62x39 but the ballistics should be as close as possible, and with a competent operator be capable of 0.5 MOA.

We purchased some H4895 and Sierra 125gr JSP to load as reduced charge .308 loads but haven't done that quite yet. Can anyone recommend this combination as far as accuracy goes?

We're considering the obvious alternative - .300 Blackout with 125gr bullets loaded to around 2350 fps. Given an appropriate rifle would this be preferable to the above?

Of course a 7.62x39 bolt gun might be the simplest solution, but try finding one (we have a Zastava M85 and it broke down on the first outing within 10 rounds so it is going back).
 
Too bad I don't live closer to you.
I could bring my Rem 700 7.62x39 test rifle I made up years ago. It will get the job done.

IMG_7024.jpg
 
drifter dave said:
Try out a CZ527. Don't think much will get .5MOA out of that caliber though.
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The most accurate cartridge in the world (6mm PPC) is based on the 7.62x39 via the .220 Russian. It's not the caliber that's inaccurate, it's just the poorly made (by Western comparisons) surplus ammunition and firearms that 99.9% of folks have experience with. Even some of the surplus fare is fairly decent, just ask Ganderite.

lejarretnoir said:
Too bad I don't live closer to you.
I could bring my Rem 700 7.62x39 test rifle I made up years ago. It will get the job done.
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Trade you for some targets? ;)

Grizz Axxemann said:
Maybe a .30-30 with 125gr pills? From what I've been told the performance is comparable.
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Ahh yes, now I recall. My original post had to do with using .30-30 load data in .308 cases which are nearly identical in capacity. It was suggested that would be dangerous, though given that the .30-30's metric designation is 7.62x51R I cannot fathom how its load data would at all be hazardous in a stronger .308 firearm.

fiddler said:
CZ527 and factory PRVI ammunition will punch .5 MOA at 100 yards.

Below is 5 shots, not 4
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Impressive, though again, there are few to be had despite diligent searching and watching of the EE.
 
Would a 30 BR be close enough in power? You really need a dedicated benchrest type rifle for that kind of shooting.

I have this rifle. It was built with a heavy match barrel for the purpose of testing 7.62x39. It has deeper throat, so as to accommodate 155 gr match bullets. If I wanted to use a 7.62x39 to shoot 0.5 MOA at 200, this is the rifle and that is the bullet.

You can try the Sierra 125. I have loaded them as reduced loads for kids shooting target rifle, and they worked quite well. I suggest a faster powder than 4895. I would try 322, 135 and 3031. Wind would be an issue.

CHINESETEST1.jpg
 
Hi Ganderite, I remember that rig. If I recall you generously offered to lend it to us. I fear I would like it too much I would have to throw money at you to not send it back! ;)

Perhaps I'm being optimistic in my desire for 0.5 MOA and 200 meters. All we really need to do is be able to put a bullet into a 3" square at that range with reasonably consistent results. The majority of our testing is conducted at 50 and 100 meters so the CZ527 ought to be suitable, especially given fiddler's results above (is that typical with good quality ammunition or a "best ever" accomplishment?).

A single rifle/platform for performing tests with .308 and downloading to 7.62x39 velocities would definitely be attractive however I suspect accuracy would suffer due to a mismatched barrel twist with one of the two weights and velocities.

amosfella said:
How about a 6.5x39?? Proline shooters had a cz 527 in stock a few weeks ago...
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We would like to stick to a bullet diameter, weight, construction, and velocity as close to 7.62x39 as possible. The goal is to verify product function with that caliber without having to succumb to the pitfalls of surplus guns and ammunition. The 7.62x39 is sort of a "worst case" scenario as few other popular cartridges bleed velocity as quickly, so if our product works consistently with 7.62x39 it should work with just about anything else bigger and/or faster. We test routinely with .223 55gr FMJ, .308 150gr SST and 147gr FMJ, and .17 HMR 17gr and 20gr JHP.

We would also like to develop consistent and accurate data to publish for our customers that gives them a practical range scenario so they are not experiencing partial detonations or misfires. The 7.62x39 is already traveling below our recommended 2000 fps minimum at 100 meters (1900 fps) and given the proliferation of the cartridge in the sporting market it would be prudent to know where one should stop.
 
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The 30-30 125gr idea may have merit for you. I would stay away a rifle with a tube magazine so that you can use spitzer bullets though. Couple of savage models come to mind 99 being one of them. 2c
 
H4895 would be a good powder for max loads in a 308 with 125 grain bullets.

H4198 or even SR4759 would be better, and if the 308 is capable of 3" @ 200 m with full power loads, then it will do it with a 125 grain bullet at 2300 fps with these powders.

I have a ptg reamer for 7.62x39 with a long tapered throat and a 0.299 pilot for re chambering shot out 308 match barrels to plinkers with surplus ammo. No surplus ammo I've tried will go 1.5 moa but can come close. Commercial bullets will do it easy.
 
Best would be to use Ganderites rifle. :)

You could also use Hodgdons 60% rule with H4895 and a 125gr bullet in an accurate .308 rifle. Their max load is 46gr, the 60% load is 27.6. Somewhere around there you should be able to get 2300fps or so.
 
So will a 7.62x39 from an SKS ignite your product at 100 yards? I want to add a exploding target to my lineup for my clients to shoot, and they shoot lots of 7.62x39 and .223. I know the .223 is no problem.

What is a recommended distance to be from a half pound, anyway?:dancingbanana:
 
My CZ 527 cuts 1/2" at 100 yards with a 25gr dose of H4198/Privi brass/Fed mag primer and a 125 Hornady SP with my 54 year old eyes and a 4X Leupold.Harold
 
Gatehouse said:
So will a 7.62x39 from an SKS ignite your product at 100 yards? I want to add a exploding target to my lineup for my clients to shoot, and they shoot lots of 7.62x39 and .223. I know the .223 is no problem.

What is a recommended distance to be from a half pound, anyway?:dancingbanana:
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The 7.62x39 is usually sufficient at 100 yards however depending on the ammunition it may be traveling slower than the 2000 fps minimum at that range and cannot be guaranteed to ensure full detonation. Quite frequently the combination of surplus ammunition and surplus firearms with iron sights equates to many grazing shots at that distance and partial detonations.

We therefore recommend the 7.62x39 and .17 HMR be used at 50 to 75 meters only. Shots at 100 meters and beyond we recommend higher calibers and magnified optics.

Our revised minimum safe distance of 50 meters was recently approved by ERD, though for safety we always recommend 100 meters.
 
Long ago I did a ton of work with 762x39 bolt guns and could never get any decent accuracy out of them, even with Lapua ammo.

I've been deep in the 300 Blackout world for a long time and very few rifles in that caliber will produce the accuracy you are seeking.

Downloading larger cases like 308 tend to produce carp accuracy.

The only thing I can think of that is going to produce the performance you are after is a 30BR. It is super accurate and designed to launch 125gr bullets.
 
When you say "replicate" the ballistics of 7,62x39, I assume you mean the cartridge, not the gun itself, unless I'm reading this wrong. Anyway, the closest you might get to it is with the 6.8mm SPC. Developed by Remington for US Army Special forces. I was meant to get closer to energies of 7.62 compared to standard 5.56Nato but maintaining Nato's better accuracy than the 7.62's. I'm guessing the 5.56's penetration through solid structures is a problem in real combat. The caliber is a hair smaller but velocities/energies close enough. The only thing I'm not sure about is the .5 MOA accuracy, that is a bit tall order. To achieve this kind of accuracy, you basically need to reach for a cartridge that was specifically developed for that purpose,which none of those that are ballistically close can achieve. I played with 7,62 myself and the best I was able to achieve was MOA 1.8. I'm pretty sure .5 is actually physically impossible to achieve due to components available on the market, you need monolithic bullet for this kind of accuracy, lead or steel core in copper jacket makes it inherently less accurate.
 
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