Is This A Sign of Overpressure?

[DaisyCutter]

Below is an image of some of my .44 Mags.


The two cartridges on the left have been fired, resized, and cleaned. The two on the right are brand new.




Note the relief area under the rim (see arrows). The image doesn't show it perfectly, but on the used cases, the relief area is expanded/swelled out to roughly the same diameter as the case wall. On the new cases, the relief area is very pronounced.

On the used cases, in some areas, I can't even snag a fingernail when running it under the rim. On the new cases, I can feel the relief area very well.

I know this happens after I fire the brass. From the percentage like this in the reload pile, I know this only happens to one particular loading. I presume it's my hottest load.

My hottest load is 23 grains of Alliant 2400, with a CCI 350 magnum primer, behind a 210 grain Speer jacketed HP. My median cartridge OAL is 1.605", but it can vary between 1.602-1.608".

Per the Alliant website;




So Alliant says I'm good to 23.5 grains. However, I'm using mag primers. I'm shooting this in a Ruger Super Blackhawk and Redhawk. The revolvers don't seem to care. They function fine, no binding, no bullets jumping crimp, just a big flash/bang.



Is this a sign of overpressure, or just a normal sign of "used" brass? Is the brass still safe.


FWIW, the headstamp appears normal, no splits, and primers looked good.

 

[rcmodel]

If they eject normally, it could just be soft brass.

What brand of brass is it??

I would probably continue to use it unless you start having case cracks or seperations.

While planning to buy some Starline brass next time.

rc

 

[Certaindeaf]

Why don't you jam a new one up the diehole and see if that makes them look like that. Can't hurt and might tell you something.

 

[DaisyCutter]

I crammed a couple new ones up the resizing die, and they still have the nice relief area.

FWIW, primer pockets are still tight for the used ones.

The cartridges eject fine after I shoot 'em.


The headstamp is as deep as when new. The brass is Winchester. I got 4 bags of 100 for $16 a bag. It was marked at twice the price, but the store owner told me he'd sell it to me at $16/ea if I agreed to buy all he had (4 bags). He said he wasn't moving any reloading stuff and just wanted the stock gone.

So I've got Winchester brass coming out my ears.

 

[rcmodel]

Well, maybe stop using Mag primers with 2400.

It isn't necessary, or generally recommended.

There have been several cautions through the years from Bryan Pearce in Handloader magazine about unexpected pressure spikes & such with Mag primers & 2400.

rc

 

[cfullgraf]

You do realize the resizing die does not resize all the way to the extractor groove?

Besides the part of the case in the shell holder, there is a little bit of the die that does does not resize the case due to the radius at the mouth of the die.

What you are seeing is just the burnishing from the part of the die that actually does touch the case. If you tumble after resizing, I find the "ring" gets polished out and you do not see it.

 

[Josh45]

I would ditch the magnum primer as 2400 doesn't need it.
Load up about 5 of them without a mag primer and see if it changes.

 

[beatledog7]

Looks like normal expansion to me. Use non-magnum primers with 2400.

I'd load a few about 10% lighter, shoot them, and compare. My bet is they look exactly like the ones that have you concerned. I doubt you'll find much difference in how they shoot either.

 

[DaisyCutter]

I've probably got 60-70 of the magnum primed 2400 hot loads left to shoot.

After that, I'll probably tone my load down a couple grains. The .44 is still a heavy bullet, and I can live with a ~1300 FPS just fine versus the max 1500FPS.

 

[Certaindeaf]

You do realize the resizing die does not resize all the way to the extractor groove?

Besides the part of the case in the shell holder, there is a little bit of the die that does does not resize the case due to the radius at the mouth of the die.

What you are seeing is just the burnishing from the part of the die that actually does touch the case. If you tumble after resizing, I find the "ring" gets polished out and you do not see it.

I hear you. I can't really see the picture/issue that well and thought what the hey.

 

[CraigC]

Pressure signs are meaningless in straight-walled pistol cartridges. Trust your data, verify with a chronograph.

 

[243winxb]

not normal Over pressure.

the used cases, the relief area is expanded/swelled out to roughly the same diameter as the case wall. I know this only happens to one particular loading. I can't even snag a fingernail when running it under the rim. I presume it's my hottest load.

 

[918v]

Normal.

 

[DaisyCutter]

Was hoping for more of a consensus.

For those who state overpressure, can you clarify as a gross overpressure or just minimally overpressure?

 

[ColtPythonElite]

cfullgraf said what I was thinking...looks normal to me.

 

[JLDickmon]

load it til it cracks

 

[918v]

When you fire a full-house load, the base will expand. The base is thicker than the rest of the case wall and will resist sizing more. Hence, it will be shinier after you're done.

 

[beeenbag]

I would ditch the mag primer if it was me...

Why don't you load up a couple, as suggested above, with regular large pistol primers and see what they do? I would do this before shooting what you have left and see if the problem persists. If you still have this with the non magnum primers then you know it is just soft brass. If you don't have it with the non magnums, pull the bullets in what you have loaded.

I really love using 2400 in my .44 magnum. I use 21g. under a 240 xtp for my deer hunting load. 21g. for a 240 is max. I have not seen the issue you have.

 

[243winxb]

a gross overpressure or just minimally overpressure?

Need pressure testing equipment to know for sure. Brass yields at different pressures depending on its hardness. Your brass is moving & i feel its not normal. To much flow for only one loading. Cartridge Brass-
Material is 70 copper/30 zinc with trace amounts of lead & iron , called C26000. Material starts to yield at 15,000 PSI when soft (annealed), and 63,000 PSI when hard.
Material yields, but continues to get stronger up to 47,000 PSI when soft, and 76,000 PSI when work hardened.

 

[918v]

Your brass is moving & i feel its not normal. To much flow for only one loading

My 357 brass looks just like it after firing 38 Special level loads. It's the sizing die causing this shiny mark. It's normal.

 

[Krogen]

Perhaps I'm missing DaisyCutter's point, but I think he's talking about the groove right above the rim, not the shiny part of the case. If he's saying the groove is expanding out to the surface of the case wall after firing, it would sure get my attention! The case head is solid in that area. If that part is expanding to that amount, something really strange is going on.

Daisy Cutter: Have I understood correctly?

 

[ArchAngelCD]

I don't think it's overpressure for more than 1 reason. First, you said the cases fall right out without binding. Second, I would think the case would swell well before the base of the case which is much more stiff.

BUT, I would stop using a magnum primer after you get through shooting the cases that are already loaded. As said above, 2400 does not need a magnum primer and magnum primers are reported to cause pressure spikes when used with 2400. I would not however drop the charge weights unless you see excessively high velocities when the ammo is shot over a chrono. (IMHO or course)

 

[DaisyCutter]

Perhaps I'm missing DaisyCutter's point, but I think he's talking about the groove right above the rim, not the shiny part of the case. If he's saying the groove is expanding out to the surface of the case wall after firing, it would sure get my attention! The case head is solid in that area. If that part is expanding to that amount, something really strange is going on.

Daisy Cutter: Have I understood correctly?

Exactly, it's the groove under the rim. The new cartridges have a pronounced groove. The used ones have little/no groove. It's not optical, I can feel it.

 

[armarsh]

From the 5-6 manuals I looked at you are at or over max. Here is what quickload has to say:




It is strange you are not having extraction issues or loose primers if the load is causing the head to expand though. Maybe the relief cut is not really below brass level and you are feeling a burr which gets ironed out with this fairly warm load. Until primers start to loosen I don't think you are in trouble.

Another thing to think about is that Gold Dots are plated bullets. Other jacketed bullets would probably be something to consider with your full-on loads.

 

[beatledog7]

Now I'm really wondering, how can a case suffer that kind of expansion in the extractor groove and not show any typical sign of overpressure?