Anyone care to speculate as to what if any obstacles would prevent me from making some high quality 7.62x39 cases from 6mm PPC

That is a considerable expansion of the neck diameter. Also, the cases are not really very similar except as to head diameter and overall length. Having said that, it is obviously possible, but may take a bit of experimentation to identify all the steps to make it work really, really well..

I suspect your luck will be better if you use only decapped (new might be best) cases, so there is no air trapped in the case during any part of the re-sizing process. I also suggest a lot of inside the neck lube and a good, long, shallow taper, expander. You will likely also need to be sure the outsides are evenly lubed pretty much all over, as the case tapers are different. Because of the expansion, overall case length may come out a hair shorter than you really want, and length trimming (to make sure the length is even all the way around) may well be necessary, making it even shorter when finished.


The only way you can know for sure is to try it, but I wouldn't buy a bunch of PPC brass to start with unless you have a PPC-chambered rifle to shoot it in if you don't like the way the project goes.

I hope it works for you, but I suspect you may just find it better to buy decent quality 7.62x39 brass to start with. Quien sabe?

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I hope it works for you, but I suspect you may just find it better to buy decent quality 7.62x39 brass to start with. Quien sabe?

but that's the rub of the matter. WHO'S quality 7.62x39 brass? Remington has gotten out of the business of making their wonderful small primed cases. Lapua is always an option but somehow I don't think lighting only 27grs of powder with a large rifle primer is going to be really conducive to accuracy. Hopefully I'm wrong about this but I doubt it as All other precision cartridges of this size use small primers

Try it on a few and see . Best of luck.

You might try to size some .243 cases to .308 just to get a feel. roger

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Originally posted by Krochus:

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I hope it works for you, but I suspect you may just find it better to buy decent quality 7.62x39 brass to start with. Quien sabe?

but that's the rub of the matter. WHO'S quality 7.62x39 brass? Remington has gotten out of the business of making their wonderful small primed cases. Lapua is always an option but somehow I don't think lighting only 27grs of powder with a large rifle primer is going to be really conducive to accuracy. Hopefully I'm wrong about this but I doubt it as All other precision cartridges of this size use small primers

I'd use the COW method to blow the new Laupa case out. I had a 7.62x39 build used a 1/15 twist barrel for the 125/135gr bullets and I had some of those old cases with the small primer pocket and some new ones with the larger and in my rifle the small primer pocket shot better.

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Originally posted by Krochus:
but that's the rub of the matter. WHO'S quality 7.62x39 brass? Remington has gotten out of the business of making their wonderful small primed cases. Lapua is always an option but somehow I don't think lighting only 27grs of powder with a large rifle primer is going to be really conducive to accuracy. Hopefully I'm wrong about this but I doubt it as All other precision cartridges of this size use small primers

I can't really disagree with what you say, but have a few comments which MAY interest you.

1. I shot a .30 PPC in bench rest for a while, and I found the difference as to whether the small primer loads or large primer loads shot better depended mostly on the rest of the load, not particularly just the primer size itself.

That is, some loads with large primers shot very well, while some did not. Ditto with small primers.

One thing which did not work well for me in that small case was "magnum" primers, whether small or large rifle magnums. That was true for my particular loads when using either stick or ball ltype powders.

2. Most of the time, the limiting factor for acuracy semed to be the rifles themselves (and maybe the shooters). Very, very few shooters have sufficiently good bench technique to be able to distinguish positively any difference between the accuracy potential of a large primer-fired load and a "small primer" ignited one. Even fewer rifles that are not built to BR standards are capable of statistically differentiating between large and small primers.

So, what are you looking for in terms of accuracy? What kind of rifle is the round to be fired in? What weight (and quality) of bullets do you plan to use? The answers to those questions may very well outweigh any advantage to either primer size.

anyway, no one else than you will be able to provide the correct answer for you. As Roger & I both suggested, the only way to know if the cases are good enough for your purposes and whether they are worth your trouble or not, is to try making & using two or three of them. Then you will know the answer for absolute certain and won't have to worry about "theory".

Good luck,

AC

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So, what are you looking for in terms of accuracy? What kind of rifle is the round to be fired in? What weight (and quality) of bullets do you plan to use? The answers to those questions may very well outweigh any advantage to either primer size.

I'm loading for a shilen barreled Stevens 200 so far my better 100yd 5 shot groups with 110g bergers and V-maxes run in the mid .3's using small primed sorted R-P cases. I hope I can improve apoun this with more load development, I certainly don't want to go in the other direction once I wear my current supply of cases wears out and if some high quality small flashholed cases help shrink my groups even more .......

Have you tried Lapua brass? I know you have your heart set on small rifle primers, but have you given the Large primer Lapua a try? K&P(Lapua) is all I use in my ASI mini 30 and it shoots pretty good. I have quite a bit of new Rem brass that I do not use any more as the K&P(Lapua) is hard to beat. I stocked up on the K&P brass about a year ago when my local shop was selling it for $18/100. Now he is asking about $39/100.

Krochus, one of the options is to ty some Lapua brass and use large pistol, or large pistol magnum primers. Many years ago Freedom Arms used to have a bushing that converted .45 Long Colt cases into small primer pockets. I wish I had acquired some of those... .210 outer, .175 inner dimensions I think it is.

How much brass are you looking for?

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Krochus, one of the options is to ty some Lapua brass and use large pistol, or large pistol magnum primers.

Tried it. The shorter primer and softer cups allow WAY too much deformation for my liking at even saami spec 7.62x39mm pressures

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P
Have you tried Lapua brass? I know you have your heart set on small rifle primers, but have you given the Large prim

That's already in the works as I do have a limited quantity of these cases on hand. I'll post the results here.

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I have quite a bit of new Rem brass that I do not use any more as the K&P(Lapua) is hard to beat.

interested in selling some of those remmy cases?

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Originally posted by Krochus:


interested in selling some of those remmy cases?

I'll look tonight and see how many I have and let you know.

Krochus, PM sent.

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Originally posted by Krochus:
Anyone care to speculate as to what if any obstacles would prevent me from making some high quality 7.62x39 cases from 6mm PPC

Why bother when you can buy Lapua cases in that caliber??

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Why bother when you can buy Lapua cases in that caliber??

Because as good as lapua is it's only as good as the large primers you have to seat in it.

27.5grs N-120 + a nice hot large rifle primer = not a great combination for knife edge accuracy

If you start with Lapua .220 Russian cases, neck up to 6mm then 7mm in two steps, turn the necks, you can use small rifle primers.

I have seen .30-PPC cases made from 7.62x39 brass and fired with large Winchester rifle primers shoot 210 grain CAST bullets into groups in the 0.1"s and 0.2"s using 27+ grains of N-133. Admittedly those were not from factory chambers or rifles, but the large-rifle primers did their part just fine. (The rifles were built by David Lee and Jim Borden.)

I doubt that there is anyone here that could tell one group fired with large primer pocket brass compared to small primer pocket brass.

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I doubt that there is anyone here that could tell one group fired with large primer pocket brass compared to small primer pocket brass.

I wouldn't bet on that

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Originally posted by Krochus:

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I doubt that there is anyone here that could tell one group fired with large primer pocket brass compared to small primer pocket brass.

I wouldn't bet on tha

So what does this show us?

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So what does this show us?

That I'm not shootin some 4MOA commie rifle and for me even a .100" increase in group size is unacceptable.

NO benchrest rounds use LR primers. Why do you think that is?

I shoot 1000 yard benchrest and my cartridge uses a large rifle primer. The small rifle primer doesn't work too well when I scotch tape it in the primer pocket.
An awfull lot of the Hunter class guys use large benchrest primers in a lot of the Hunter class cartridges. So Krochus, you are a little off base.
If you are old enough you might remember when the old Sako 220 Russian ran out and guys had to try what they could get. We tried everything just to be able to shoot and the 7.62 X 39 allowed that and they had big primer pockets. Tha brass was shit but we could shoot. Then Sako came out with new PPC brass but it was soft and then Norma came out with PPC brass and it was better but when Lapua came out the problem with the PPC brass went away. So if you really want to shoot, you have to use what you can get and it sounds like you want only small primer pocket brass. That's OK! But not all benchrest rounds use small primer pocket brass!

OK here's the skinny on using the LAPUA LR brass

I just tested a load ladder using the same bullets and powders that my best small primered load used.

The accuracy showed some pretty good potential but the problem is the LR primed brass couldn't handle it's drink nearly as well. Only 26.0grs of N-120 was producing a ring above the case head that was worse than my RP cases after 6 or 7 firings of 27.5grs. I wouldn't dare reload these cases even once.

It's late but I'll get some measurements offin those cases later

So I was right but not in the way I expected.

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Only 26.0grs of N-120 was producing a ring above the case head that was worse than my RP cases

Would you mind posting some pictures of both cases?

Did you measure the "head to shoulder" of the Lapua brass before and after firing?

Without seeing the brass I can't say for sure, but the ring you speek of may be caused by too much head space and the brass steatching to fill the chamber and not high pressure.

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Did you measure the "head to shoulder" of the Lapua brass before and after firing?

Yes, I had a chamber gauge made to go with this bbl. The lapua cases had the shoulder set to the same place my Remington cases did. I don't think that's what this is as I've never actually seen a incipient separation as low on the case as these were (just above the extractor groove) and it it were a headspace issue the stretching would have been just as bad with the lighter charge weights, which it was not.

The pic below depicts the measurment just above the extractor grove made with a Lufkin mic

Without having the brass in my hands they appear to be fine. The shiny area around the case head is the point where the web ends and the thinner case wall expanded to chamber dimentions when under pressure, this is normal.

For proper expansion measurements your mic should be able to read to the .0001. Without starting another fight on this forum, there are many, many experts here that believe these measurements are not a good indicator of pressure.

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many experts here that believe these measurements are not a good indicator of pressure.

I agree with that group, However these measurements can be a good indicator of whet brass life will be like. No matter how expensive they are or how far away the factory is when you have a brand of cases expanding twice what another brand does with slightly less accuracy that means they are inferior in my book.

The pictures do not do a very good job of depicting how bright and well defined the ring is. It's pronounced enough that I only fired one round the highest charge of 27.0grs and I did that facing away from the rifle

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Originally posted by Krochus:


NO benchrest rounds use LR primers. Why do you think that is?

Apparently you did not see this post, or chose to ignore it for some reason:

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Originally posted:
I have seen .30-PPC cases made from 7.62x39 brass and fired with large Winchester rifle primers shoot 210 grain CAST bullets into groups in the 0.1"s and 0.2"s using 27+ grains of N-133. Admittedly those were not from factory chambers or rifles, but the large-rifle primers did their part just fine. (The rifles were built by David Lee and Jim Borden.)

The groups mentioned in this post are some 0.300" to some 0.400" smaller than the groups you posted pictures of, and they were fired by three guys I know and shot a lot with. Two of those guys were U.S. National BR champions, and the other held about 10 U.S. National BR Records at one time. While it is true that much of the time they used SR primers, other times (and with other loads) sometimes they used LR primers. We (they and I) used to try everything we could think of by way of cartridges, primers and powders. To be honest, we didn't find any appreciable difference between primer brands or sizes when it came to accuracy. Some loads didn't shoot well with large rifle primers, and other loads didn't shoot well with small rifle primers. Some didn't shoot well with Federals, and some didn't shoot well with RWS, and on and on. It isn't the size of the primer that is of importance, it is the shooter, the rifle, the bullet, and most of all, the load development work done.

And I will agree with the other posters who said here that most shooters can't shoot well enough to get anything statistically meaningful between the two different sizes....especially with a rifle and load that are only capable of half inch groups to start with. That's not a good enough tool to tell the difference with, even by the best shooters in the world.

Now, you can flame on if you want, but I believe that to be a pure and simple fact.

I will of course, defend the view that you are welcome to use any size primer you want, and if you believe it will help you, it will. That's called the placebo effect and it is a genuine consideration, but it is not a sound basis for making universal statements.

I hope you just go ahead and make some of the cases you have asked about, and see whether they help YOU. If they do, then you should keep using them. If they don't, maybe you will have learned something from first hand experience.

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That's called the placebo effect and it is a genuine consideration, but it is not a sound basis for making universal statements.

Well I'll be damned all this time spent tailoring loads to specific rifles wasted because according to YOU!! unless your rifle is capable of 1/8th moa that just any OL component will do. I wonder if WOLF sells bullets

As I stated previously it turned out that my accuracy with LR primers wasn't too far from what the smalls were producing. But what wasn't similar was brass strength. LR brass would have to be awfully cheap to be worthwhile since you're only going to get 1 or 2 loadings in my rifle before it's trashed.


So far since posting this my course of action has been to buy up as many RP cases as I can get my hands on. At some point I may buy up a bag of Silver State 6ppc cases to try experimentations on

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Originally posted by Krochus:

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That's called the placebo effect and it is a genuine consideration, but it is not a sound basis for making universal statements.

Well I'll be damned all this time spent tailoring loads to specific rifles wasted because according to YOU!! unless your rifle is capable of 1/8th moa that just any OL component will do. I wonder if WOLF sells bullets



As I stated previously it turned out that my accuracy with LR primers wasn't too far from what the smalls were producing. But what wasn't similar was brass strength. LR brass would have to be awfully cheap to be worthwhile since you're only going to get 1 or 2 loadings in my rifle before it's trashed

You can be incensed if it makes you feel better. That's your privilege. Anger won't help your loads or your shooting. Nowhere did I say any old component will do. What I said was that with some loads, large primers are superior, and with others, small primers are superior. The hard part is taking the time and doing the work to find out which works best with which load.

As to your brass life, there are numerous possibilities as to why the loads you have tried have short brass life with some brands of brass. For one thing, you MIGHT be using a powder that is a little too fast for that cartridge. We had much better luck with N-133 and N-135 in our .30 PPCs.

Another might have something to do with how you treat your cartridge cases, and/or the dimensions of your chamber. We shot cases that we intentionally turned to sizes such that we never had to size the cases. That gave us as close to perfect headspace as possible after fire-forming, and prevented excessive sizing down and then re-expanding of the brass.

I know this will not please you either, probably, but with the type brass I am speaking of, we had no trouble at all getting brass life in the hundreds of reloads per case. And that is with both large and small rifle primers.


Anyway, it is obvious you have had enough suggestions here as to how to make small primer cases from the PPC cases. If you want to do it, then have at it. No one is stopping you. They are just questioning the conclusions you have arrived at as a reason for doing so.

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For one thing, you MIGHT be using a powder that is a little too fast for that cartridge. We had much better luck with N-133 qnd N-135 in our .30 PPCs.

That's certanlly possible, But with only 110grn bullets? I dunnow as I haven't yet been able to find the case capacities and external dimensions listed anywhere for 30ppc to compare to.

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Originally posted by Krochus:

That's certanlly possible, But with only 110grn bullets? I dunnow as I haven't yet been able to find the case capacities and external dimensions listed anywhere for 30ppc to compare to.

I certainly can understand why you make this comment. One would think that with 110 gr. bullets it would be hard to find a rifle powder which is too fast. But one can never tell. If it was mine, and IF I had easy access to them, I would TRY some powders which were both a little slower and more bulky in my large rifle primer cases. Sometimes that seems to make a difference, though I am not certain why.

I also believe for sure I would try some heavier bullets. Not really, really, heavy bullets, but there are a lot of approximately 125 and 130 grain match-quality bullets out there used by the .30-BR folk. You should be able to find a bunch of them at BR.com . With the heavier bullets, a little slower powder just might be outstanding. (Or it might be a complete flop, I grant you.)

I'd also use my chronograph to find what velocity range my most acurate loads are in, even if they are destroying brass. Then, I'd try appropriately larger amounts of slower burning powders to see if there was something I could get the same velocity from, with lower pressures. IF I could do that and still get about the same accuracy, I would expect that might improve brass life somewhat.

Anyway, good luck with your search.

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I also believe for sure I would try some heavier bullets. Not really, really, heavy bullets, but there are a lot of approximately 125 and 130 grain match-quality bullets out there

thus far the only heavier bullets I've used are the speer 125grn TNT, accuracy wasn't nearly as good as with the 110grn bergers and v-maxes. Granted the speers were loaded over AA1680

Given the 1-15" twist I don't know what the upper limit on bullet weight would be within my velocity envelope

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I'd also use my chronograph to find what velocity range my most acurate loads are in, even if they are destroying brass. Then, I'd try appropriately larger amounts of slower powders to see if there was something I could get the same velocity from with lower pressures. IF I could do that and still get about the same accuracy, I would expect that might improve brass life somewhat.

So far the faster I go the more accuracy I get. My best loads shoot in the high to mid .3's pushing 110 grainers to a speed of just under 2800fps, I'll try some slower propellants H-335? but A slower powder would have to be pretty compact, my pet load of 27.5grs of N-120 is a case full.


I'm more intrested in the small flash hole on PPC cases more than anything.

Krochus,

have you tried the LP Winchester brass yet?

Rich
DRSS
Knowledge not shared is knowledge lost...

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Originally posted by Idaho Sharpshooter:
Krochus,

have you tried the LP Winchester brass yet?

Rich
DRSS
Knowledge not shared is knowledge lost...

I have but not in this rifle.

What was the "head to shoulder" measurement and grains of water of your new Rem and Lapua brass?

What is the head to shoulder measurement and grains of water with once fired brass?

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Originally posted by Krochus:

thus far the only heavier bullets I've used are the speer 125grn TNT, accuracy wasn't nearly as good as with the 110grn bergers and v-maxes. Granted the speers were loaded over AA1680

Given the 1-15" twist I don't know what the upper limit on bullet weight would be within my velocity envelope

I'm certainly not surprised you did not get as good accuracy from the Speers as from the Bergers. The Bergers are generally of custom bullet, match, quality. Speers are mass production bullets through and through...often about like buying Winchester or Remington bulk bullets in terms of quality for match use. Don't get me wrong, I like Speer bullets very much for hunting or plinking use. But they seldom deliver match winning accuracy potential. They are not intended (or priced) to.

To shoot the best possible groups requires the best possible bullets. You really DO need to visit the IBS BR website and look through what is available to and in use by the guys shooting in Hunter Class benchrest competition. They are mostly not using exactly the same cartridge as you, but ones very similar in size, powder capacity, and performace.

As to the twist issue...the way you find out what will stabilize in your gun is by trying them in your rifle with your loads. I do know that guys shooting hunter BR .30s definitely use twists as slow as 1 turn in 15" (like yours). Some use even slower twists. Stability depends on so many issues in addition to bullet length (not weight, but length is the primary consideration) that trial in your rifle is the only real proof of the pudding.

For any who are interested, here is the BR website, for those who wish to check out the BR shooters tools. One caution...those guys are at least as inflexible in their views as those of any other forums, and many of the posters there are wannabes, just like everywhere else...that is to say, just as long on theory and short on first hand real-world experience. Still a good site, if one treats it like anywhere else and makes the effort to glean the wheat from the chaff.

http://www.benchrest.com/

Best wishes,

AC