Pressure signs or not?

R

RandyInTX

Inactive
I've returned from the range after shooting my first batch of reloaded 9 mm. As I went to decap and size the brass, I noticed what I'm pretty sure are what I've seen described as "flowing primers," a fairly late pressure sign. Sadly, my range brass isn't very well sorted -- it's a topic for a different forum, I guess, as to how to corral one's own flying brass at a public range -- so I can't group them strictly by load, but I can at least tell which powder was used. Load data for this first batch came straight off the instructions that came with the Lee carbide die set for 9 mm. All shots were fired out of a Beretta 92S, one of these surplus Italian police sidearms, which appears to be in very good condition and shows no sign of misuse or having fired tens of thousands of rounds. All brass was bought as range brass, so I don't know how many loads they've seen. All rounds were topped by 125 gr Missouri Bullet Co. semi-wadcutters, HiTek coated. They're listed as.356 and Brinell hardness 18, if that matters.

Speer nickel-plated, mix of regular and +P brass
CCI 500 small pistol primers
15 each of 3.8 gr, 4.0 gr, and 4.2 gr Universal
Lee Factory Crimp Die about 3/4 turn past contact
COAL ~1.124"

Winchester nickel-plated brass (might have also been a mix of regular and +P)
CCI 550 magnum small pistol primers
15 each of 3.8 gr. 4.0 gr, and 4.2 gr Titegroup
Taper crimp applied with Lee bullet seating die only
COAL ~1.118"

As I hope you can see in these pics (with a few unstruck primed cases for comparison), all of them seem to have the "flowing primers" to some extent. As a group, I couldn't tell a big difference between the Universal/LPP and the Titegroup/MagnumLPP rounds.

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IMG_0490.jpg

IMG_0491.jpg


Thoughts?

Randy...
 
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You're not actually using Large pistol primers are you? Also all the CCI primers I can recall using are silver looking. Yours are brass covered and look like other brand. Or maybe CCI switched primer material at some point.

That definitely looks like excessive primer flowing. Assuming the rest of your description is correct I'm not sure what would cause that. Did you ever check to see if the rounds are being pushed back into the brass once chambered. Maybe a faulty crimp is allowing bullet set back...

If you try the same loads again take different colored permanent marker to the head stamp. I use blue, red, black to keep track of different loads. It also helps identify my brass from other range pickups
 
The primers themselves are not flattened at all. I would expect some flatening of the primers if the pressure was that high to cause them to flow and crater.

Like Reddog implies, I hope you're not using LP primers in 9mm.
 
Gah, sorry...I've been looking at rifle stuff today and partially misspoke. These are CCI 500 and 550 *small* pistol primers. Will edit the OP.

Also, these are silver colored. The pic was just taken in very warm light.
 
Guys,

Good luck fitting a large primer in a 9 mm case. Not going to happen. It would just crush.


Randy,

When primer pressure gets high, the shoulder gets sharp and wide than the original primer diameter (mushrooming) and any flow into the firing pin tunnel around the primer is very sharp.

I see no pressure signs. The nice round shoulders of the perimeter says no problem. Instead, I think you are looking at something that is an artifact of the shape of the breech face of the gun around the firing pin tunnel in the slide. I would look and see if you can't see it.
 
First of all, you can't put large pistol primers in a 9mm. CCI's are silver though, could just be the photos. There are no signs of pressure, and your loads are well within the book data. Those strikes are normal for a Beretta.

Here are signs of very high pressure. Left case is normal, right case primer is flat and flows to the edge, head stamp is pretty beat up, case bulge at the rim, extractor mark because it was much harder to get out of the chamber.

image36874.jpg


Normal Glock strikes with CCI primers, notice the rounded edges

image36648.jpg


cases bulges from a Major Open 9mm, 125 grain going 1,400 fps

image36326.jpg


case rupture from a Major Open 9mm, shooter thought it was once fired brass, once too many times...

image37150.jpg


By the way, don't ever use these head stamps, Freedom Munitions (FM), AmmoLoad or IMT. They have a stepped case and will separate during firing. The bullet goes out, the back end of the case gets extracted, and leave you with a little sleeve stuck in the chamber and a dead gun.

image36944.jpg
 
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Randy in TX,
I have overloaded a lot of 9mm brass to see what happens and it looks more like 9x45's pictures than yours.

Your pics do remind me of a brass going through my Win 92 25-20 made in 1900 that must have shot a lot of primers that leaked and eroded the firing pin hole in the breech face. I can only get ~ 25 kpsi before small magnum rifle primers will pierce.

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Look familiar?

Do you really have a Beretta 92S?
Italian police trade ins?
I was getting those for $240 from Century in 2007.
I modified standard Beretta 92FS magazines to fit.
Those magazines are hardened steel, and I have to mill them out with carbide.
 
Clark's an engineer who has done gun testing professionally, so he probably has had access to a universal receiver and a pressure transducer or copper crusher barrel. I use the Pressure Trace strain gauge instrument and find it generally satisfactory, if you are looking for a method that doesn't cost thousands of dollars. There are also a couple of methods of estimation from velocity that can ballpark you if you have two-point pressure data from manufacturer, like Hornady. Or you can calculate it in QuickLOAD and adjust its powder properties to arrive at a close match to the commercial data points, then use that model to see what you've got going on. Compared to the Pressure Trace results, I've gotten some fairly close estimates that way.
 
I have access to a lot of stuff, it does not mean I got off the dime and do stuff.

When I have Quickload predicting the pressure in a bottleneck rifle that matches the chronograph, I probably know what load will make loose primer pockets for that case head design. So i am working in QL pressure. They call it psi, but i just have to used it, and not trace it to the NIST.

And the 25-20 is bottleneck.

QL prediction primer piercing in a good 9mm pistol would be nonsense.

QL is like a Valhalla power factor meter in the 1980s. You know it is working when it gives you the right answer. So far, QL is working and predicting pressure correctly for me when it is agreeing with the chronograph.
 
I'm a retired engineer and am familiar with units of pressure, having designed and built gas flow/pressure measuring systems for decades. I have used piezoelectric dynamic sensors, especially low voltage outputs, so the computer has a value for the algorithm logic to determine switch points. So the first thing is do not use acronyms without definitions, you know, like your college text books. psi = pounds per square inch, psig = pounds per square inch gage, and absolute pressure = atmospheric pressure plus gage pressure. NIST, as it is now known, the National Institute of Standards and Technology, before 1988 it was the National Bureau of Standards. However pressure is not linear, like velocity, especially at the knee of the curve. I assume Quick Load is a software that predicts pressure, velocity and ballistics based on some data base somewhere. I see they have a disclaimer.

"It is merely a computer simulation. ....Of course the best way to check firearms cartridge loads are actual proof test measurements at certified test facilities."

The reason I asked about the 25-20 is because it was originally a black powder cartridge rated at around 20,000 psi. And the steel of the turn of the century is not the steel of today. I don't believe that software used any empirical black powder copper units of pressure (CUPs) data from the 1900s.
So the program is probably using SAAMI (Sporting Arms and Ammunition Manufacturers' Institute, in the US) data 0f 28,000 CUP. My premise is that would be invalid for steel made in the 1900s.
 
9x45,
I am sure you know more than me about this. I am a retired engineer too. The wife still works designing calibrators. Whenever i say anything about a measurement, I am probably making a mistake... or so is seems from what she says.
I was at Physio Control in 1991-94 when they were shut down by the government for out of control processes. The couple hundred engineers there were used to straighten out this paperwork problem. I had to validate and verify processes like receiving inspection. Then take the instrument to calibration. Then a long write up on a Sun workstation [remember those?]. I found out how hard it is to prove one tiny thing. And the math and effort to tie that one tiny receiving inspection measurement to NIST.
I came away with the attitude that most measurements are not kosher, not sanitary, but probably safe to eat if you can get past the smell of unknown error.

It is with this attitude that I use QL psi.
I reload some cartridges with the same Mauser case head:
22-250, 243, 6mmRem, 250S, 257R, 257RAI, 25-06, 260, 6.5-06, 7x57, 308, 30-06, 8x57, and 35W.

Those cartridges all seem to have the same threshold of loose primer pockets when compared with QL psi, when the chrono agrees with QL.

Are those psi the same as what may someday be traced to NIST?
Does not matter to the end goal of quickly developing useful loads.
Matters a great deal to the angels on the head of a pin crowd.
 
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