9mm major - Split Cases

[Hi-Power Jack]

I've been shooting 9mm major (TruBor) for three

years - all of a sudden last month, I get three

puffs of black smoke and three split cases. So

far - no one has been injured, and the gun seems

to be in great shape - mags not harmed either,

just a lot of black soot and a little scary:(

The cartridge cases were split down near the bottom

of the case (with the primer being at the bottom).

The bullets did not become lodged in the barrel.

I've lways used range brass, Been using Russian primers

for more than a year, the load is basically 7.0

grains Winchester Auto Comp, behind a Tula SPMPrimer

and a 124 gr. MG JHP, seated at 1.165".

The load works well, is accurate, and fun to shoot.

Just got the gun back from the gunsmith, and in that

month I fired 3,000 rounds thru each of my two TruBor's.

One TruBor - the one that just came back from the

gunsmith - had three explosions and split cases.

Talking to people, I get two different possibilities:

1. the range brass and Tula primers are the problem.

or

2. the gun is firing "out of battery".

I've talked to people who have loaded tens of thousands

of range brass 9mm major and Russian primers (as I have);

and they've never heard of a problem like this.

I can load up 2,000 similar rounds using new/once fired

brass and American primers, and test the problem that

way, but before I go to the bother, wondering what you

think.

I'd appreciate any insight you might have about this -

any personal experiences with range brass/Russian primers

and/or "firing out of battery".

Thanks,

Jack

[yoshidaex]

got any pics of the split cases?

We get "super face" periodically with unknown range pick up brass (multiple 9 major firings along with unknown make brass) but with once fired stuff, we never experience "super face".

[Foxbat]

I bet that was a Winchester case.

How do I know? Over some time I have accumulated a small bag of such ruptured cases, and they are ALL, without a single exception, Winchesters. Your load is fine, I shoot that load a lot, except I don't use the Russian primers - for political reasons.

Here is the most recent case (pun...) like that.

[smokshwn]

I don't know how many rounds I am at now in my 9mm Bedell but it is above 45K. All of it unsorted range brass. All of it with a similar load as yours and about half of it with Russian primers.

I had two ruptured cases early on (10K) within about a month of each other. Of course all the accusations came from the 9mm naysayers. It turned out that I had let the mainspring on my recoil master go too long and the gun was unlocking prematurely. Changed out the spring, and make sure I watch the interval a little closer and I have not had another incident at all.

FWIW both cases were Nickel Winchesters.

Edited April 10, 2011 by smokshwn

[Hi-Power Jack]

I bet that was a Winchester case.

How do I know? Over some time I have accumulated a small bag of such ruptured cases, and they are ALL, without a single exception, Winchesters. Your load is fine, I shoot that load a lot, except I don't use the Russian primers - for political reasons.

Here is the most recent case (pun...) like that.

That photo looks a lot like my three case separations.

And, the two cases I kept are both Winchester??? Not sure about the third.

I guess at least 40% of my range brass is Winchester - and I've come to prefer

it - I've actually separated some of it out and shot all Winchester brass

in some matches:(

I use the Russian primers for PRICE>>> More important to me than politics

right now:)

[Hi-Power Jack]

I don't know how many rounds I am at now in my 9mm Bedell but it is above 45K. All of it unsorted range brass. All of it with a similar load as yours and about half of it with Russian primers.

I had two ruptured cases early on (10K) within about a month of each other. Of course all the accusations came from the 9mm naysayers. It turned out that I had let the mainspring on my recoil master go too long and the gun was unlocking prematurely. Changed out the spring, and make sure I watch the interval a little closer and I have not had another incident at all.

FWIW both cases were Nickel Winchesters.

I just changed the spring - and three ruptures, pop, pop pop.

My two Winchester cases were both brass - think the third one

was also.

Sounds like it happens once in a while, and maybe I've used up

my three year supply of ruptures, I Hope?)

Thanks for the thoughts.

Jack

[lcs]

Shot thousands of 9 Major with WIN. In fact that is all I used. Once fired WIN. Never a case separation and I shot 115s.

The thing I don't like is Auto Comp. In testing with 38SC, I saw major pressure signs on the primers and could really feel it in the hand. I think there are tested and safer 9 Major powders. JMHO. You take a shorter 9 case and the pressure goes even higher.

I know, quite a few people use Auto Comp, but what is you SD with AC ?

[Sarge]

What did the gunsmith do? Seems odd to happen three times just back from the smith. It might be worth talking to them about.

[Hi-Power Jack]

What did the gunsmith do? Seems odd to happen three times just back from the smith. It might be worth talking to them about.

He reworked the gun (new springs, extractor, etc) and we've been

talking for the past two weeks.

He seems to feel it's the ammo, and NOT the gun - I'm just looking

at alternatives. Couple people tell me that kind of problem is

probably the gun firing out of battery???

[Hi-Power Jack]

Shot thousands of 9 Major with WIN. In fact that is all I used. Once fired WIN. Never a case separation and I shot 115s.

The thing I don't like is Auto Comp. In testing with 38SC, I saw major pressure signs on the primers and could really feel it in the hand. I think there are tested and safer 9 Major powders. JMHO. You take a shorter 9 case and the pressure goes even higher.

I know, quite a few people use Auto Comp, but what is you SD with AC ?

I just switched to AutoComp, and the primers look great - no signs of pressure

at all. I, too, have used a lot of WW cases, but not once fired - mine are

range brass.

The accuracy is great - just ran my last 4 from Sat's match thru a chrono

and they were within 15 fps of one another - I know that's too small a sample,

but no one could believe how close the four were.

[Bansheex]

I get some side split cases, but never had one like shown in the photo. Mine have all been cases that were Nickel Winchesters. I load 6.5grs Autocomp at 1.140 They run around 1200fps.

Edited April 12, 2011 by Bansheex

[rhyrlik]

Maybe the primer is too hot and is causing the pressure to spike. Try a standard primer.

[Hi-Power Jack]

Maybe the primer is too hot and is causing the pressure to spike. Try a standard primer.

That's one of the theories of my gunsmith.

Funny thing is I've fired 4,000 of these same rounds thru

another TruBor I have, and no problem with that gun?

So, I'm going to get some American, standard SPP, and try

them with new or once fired brass, and see if I can get

3,000 rounds thru the gun that I've been having trouble

with - see if that solves the problem.

If it doesn't solve the problem, I guess it's the gun???

Jack

[G-ManBart]

Maybe the primer is too hot and is causing the pressure to spike. Try a standard primer.

That's one of the theories of my gunsmith.

Yeah, and it's a terrible theory. What causes cases to blow out the way you're describing is pressure. I've compared lots of different primers from most Win, Fed and Wolff (SP, SPM, SR) and they usually show less than 20fps difference on the chronograph, so they're not spiking the pressure....if they were, the velocity would almost certainly spike similarly.

Look at Hodgdon's data for 9mm Autocomp loads with 125gr jacketed bullets. They show 5.2gr at 1.090" being max, and 33K PSI. So, you're loading longer (only helps so much), but increasing the charge by a THIRD....that means you're getting well into the 40-50K PSI, and cases are failing.

Loading 9 Major with unknown range brass and slightly faster powders like Autocomp is going to show any flaws in the brass pretty quickly.

Have you changed lots of powder and then rechronographed to make sure it's not different than the last lot? Are you sure you're not getting Win cases that are from NATO spec ammo (some have a smaller case volume)? Do you know if the cases are once-fired or potentially multi-fired? Way too many variables going on.

All of these things are why I don't particularly care for Major 9 (I have one)...many people try doing it on the cheap (range brass, etc) thinking it's fine, when it's really not. and wonder why bad stuff happens sometimes. And it's not just the newer folks...I watched a big name shooter/gunsmith, who loudly touts Major 9 as the way to go, have the primer melt on one of his loads...locked the gun up like a vault....yeah, that's a sure sign of a safe combination. R,

[rhyrlik]

Velocity and pressure do not have a linear relationship. Just because you saw a 20 FPS difference on your equipment does not mean squat. What blows cases is not pressure, but the shape of the pressure curve. You can blow a 9mm case with 35000 PSI just as easy as with 70000 PSI.

[Aircooled6racer]

Hello: That is one of the reasons I use the tried and true HS-6 and Silhouette powders and check every batch over the chrono. I also use 3N37 since I have some left but it is hard on primers and my hand. I also have gone to a Case Pro since it works the brass on the bottom by rolling it into shape. The "U" die puts lots of stress on the case when shot in a lose chamber. Thanks, Eric

[Hi-Power Jack]

Maybe the primer is too hot and is causing the pressure to spike. Try a standard primer.

That's one of the theories of my gunsmith.

Loading 9 Major with unknown range brass and slightly faster powders like Autocomp is going to show any flaws in the brass pretty quickly.

R,

G-Man, sounds like you think that WAC is too fast a powder to be safe in 9mm major?

Is HS6 a little slower? I have used HS6 for the past three years, and just recently

switched over to WAC - but, not having any problems with the new WAC loads in my

other TruBor?

Not possible that a part is worn, and the gun is firing out of battery?

I'm really confused??? Thanks for any suggestions.

Jack

[G-ManBart]

Velocity and pressure do not have a linear relationship. Just because you saw a 20 FPS difference on your equipment does not mean squat. What blows cases is not pressure, but the shape of the pressure curve. You can blow a 9mm case with 35000 PSI just as easy as with 70000 PSI.

Did I say they were a linear relationship? No, I didn't. Note, I said "almost certainly" when I said the velocity would increase. The reality is that they are fairly close to linear with most published combinations, and when they aren't linear, its often when they're often getting into the danger zone, or are too low to be consistent.

And you know that it's possible to blow a case with a 35K psi load as easily with a 70K psi load exactly how? If you blow a case with 35K psi, something else is seriously wrong, because a proof load is 10K higher, and shouldn't blow the case.

A case is a balloon, just one that isn't very flexible. If I put 5psi into a party balloon, no matter how fast I do it (pressure curve), the balloon isn't going to break. If I put 200psi, it's going to fail, no matter how slowly I fill it. You can't say that the pressure curve alone is the determining factor...

[G-ManBart]

Maybe the primer is too hot and is causing the pressure to spike. Try a standard primer.

That's one of the theories of my gunsmith.

Loading 9 Major with unknown range brass and slightly faster powders like Autocomp is going to show any flaws in the brass pretty quickly.

R,

G-Man, sounds like you think that WAC is too fast a powder to be safe in 9mm major?

Is HS6 a little slower? I have used HS6 for the past three years, and just recently

switched over to WAC - but, not having any problems with the new WAC loads in my

other TruBor?

Not possible that a part is worn, and the gun is firing out of battery?

I'm really confused??? Thanks for any suggestions.

Jack

There are probably too many variables to answer that question easily. Have you done back-to-back chronograph testing with the two guns to see which one is faster? Is it possible the other gun is significantly slower than the one that blew the cases? Without seeing some of the cases that blew, it's hard to tell, but the picture you said looked like your blown cases didn't look firing out of battery...those tend to have larger holes, that extend farther forward. Honestly, anything is possible, and you could have had a load that was right on the jagged edge, and a slight change was all it took to just barely push the weakest cases, or those with the smallest case volume, just over the edge.

The one rule with ballistics is that there really aren't any absolute rules, so take everything with a grain of salt. HS-6 is a bit slower, and has been used by lots of people with good results, so it's a pretty safe bet. My baseline 9 Major load is with HS-6, but I've also got data for 3N37, N350, 3N38, N105 and will be working up loads with SP-2 this year (don't bother trying to find that one).

Something seems to have changed with your setup...finding it just may not be all that easy. First thing I'd do would be to chrono a couple of 20rd strings and see what you're getting. R,

[JThompson]

I've seen a lot of powders drop in fps just before the go critical on pressure. When I was beginning to reload a friend told me when working a load to be careful if i went up on charge and did not get a corresponding up in fps. I think Clays is one of those that does that. People get looking for a certain fps and they up the load, do not see the fps go up and up it again... next thing that happens is BOOM!

I would not fire that load anymore until I had an answer to what is happening.

The primer is not the issue and it doesn't look to me like it's leaving battery to soon, but I can't be sure of that.

JT

Edited April 17, 2011 by JThompson

[rhyrlik]

A case is a balloon, just one that isn't very flexible. If I put 5psi into a party balloon, no matter how fast I do it (pressure curve), the balloon isn't going to break. If I put 200psi, it's going to fail, no matter how slowly I fill it. You can't say that the pressure curve alone is the determining factor...

No. A brass case is not a balloon. It is like any other metal container. If you fill it too fast it will rupture. If you fill it slow, it will swell.

Not all brass is the same. Some have internal defects that may not ever manifest themselves unless the cases are abused.

9mm brass is not designed for 50000PSI+, so when you run pressures up that high you should take care to gave the most gradual pressure curve possible. Primer type plays a very important role in the shape of the pressure curve. Use too strong of a primer with too fast of a powder in a small capacity case and problems will emerge. This isn't rocket science. Get Quick load and see for yourself.

[G-ManBart]

A case is a balloon, just one that isn't very flexible. If I put 5psi into a party balloon, no matter how fast I do it (pressure curve), the balloon isn't going to break. If I put 200psi, it's going to fail, no matter how slowly I fill it. You can't say that the pressure curve alone is the determining factor...

No. A brass case is not a balloon. It is like any other metal container. If you fill it too fast it will rupture. If you fill it slow, it will swell.

Yes, a case is the same as a balloon...they both expand, they just have different levels of elasticity...simple stuff really. If you fill it too fast, with 10KPSI, will the case fail? No, because pressure is the #1 determining factor in what makes a case fail, and 10K isn't enough. Sure, at the absolute edge, a steeper pressure curve, or a longer dwell time, might push a case over the edge, but that's waaaaay beyond any reasonable load.

Not all brass is the same. Some have internal defects that may not ever manifest themselves unless the cases are abused.

I said that in my first post...

9mm brass is not designed for 50000PSI+, so when you run pressures up that high you should take care to gave the most gradual pressure curve possible. Primer type plays a very important role in the shape of the pressure curve. Use too strong of a primer with too fast of a powder in a small capacity case and problems will emerge. This isn't rocket science. Get Quick load and see for yourself.

Hmmm...use too fast of a powder, in a small capacity case, running way over pressure limits and you're pretty much asking for problems regardless of what primer you use. BTW, who says I don't have QuickLoad? You do realize that QL is theoretical, not absolute, right? It's sort of interesting that nobody has ever tried to use QuickLoad to document primer brisance....oh wait, that's because it can't reliably do that.

If the load isn't seriously over pressure limits, a steeper pressure curve, or a hotter primer, simply won't make a decent case fail...period, end of story. For folks who want to push into uncharted, potentially dangerous, territory....well, they're finding out why it's uncharted territory. R,

[stringcheese]

Is it possible your cases have grown couple thousandths longer and are headspacing just out of full battery?

Could your OAL put your bullet so close to the lands that a small variance in your seating die put a bullet on the forcing cone keeping your slide .002" out of battery?

Many High Power 200M silouhette pistol shooters lightly rough up their chambers for hot loads to hold the case during ignition. It could help your problem assuming there is no roughing on the top of the chamber where the cartridge hits when entering it.

[rhyrlik]

If the load isn't seriously over pressure limits, a steeper pressure curve, or a hotter primer, simply won't make a decent case fail...period, end of story.

Conversely, if the load is seriously over pressure limits, as nearly 9mm Major loads are, then the primer may be the straw that broke the camel's back.

My research indicates that Power Pistol is the most forgiving powder in that respect.

[smokshwn]

If the load isn't seriously over pressure limits, a steeper pressure curve, or a hotter primer, simply won't make a decent case fail...period, end of story.

Conversely, if the load is seriously over pressure limits, as nearly 9mm Major loads are, then the primer may be the straw that broke the camel's back.

My research indicates that Power Pistol is the most forgiving powder in that respect.

I am assuming by using the word "research" you are referring to documented load data coming from an instrumented test barrel, correct?

Or are you just referring to uncontrolled chronograph and load data from your pistol?

Edited April 18, 2011 by smokshwn