Overpressure

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Starter

New member
Hello,
I’m new to reloading and I need some advice.
I use Berrys Bullets, 9mm, 115 grain, round nose double strike, .356 with Accurate #2 powder. The Accurate #2 load data indicated a range of 4.2 - 4.7.
Both casings in photo were loaded with 4.2 grains.
I have been informed the casing with the ripple or crater appearance indicates an overpressure and I should reduce the load.
I have used both 4.2 and 4.3 grains in both my Glock 26 and Beretta 92FS.
Never had any jamming and accuracy seemed very good.
Two questions: Am I “overloading” causing an overpressure?
Should I use Lead Cast Round nose Data which indicates 3.9-4.4 grains?
Thank you very much in advance for considering my lengthy question.
 

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It looks like the upper one was fired in a Glock, and the lower one was fired in a Beretta. These primers look normal otherwise.

Some guns leave a characteristic imprint on the fired primer because of the shape of their breech face around the firing pin hole, and not because they are over pressure.
 
Compare what you are getting with factory ammo. I have fired a few handguns that just simply leave funny markings on the primers, Glock being one of them.

From your picture, I do not see the primers flowing to fill the pocket this would be what we call a flattened primer, and is a good sign that you are getting up there im pressure.

Another good way to check for pressure is to look for the webbing to bulge. If I see this in an autoloader, I'm backing off the charge.

If I was the one making that load, based on the information you have provided, I would likely be happy with what you have. You said it is functioning the pistol fine and the accuracy seemes to be there. Your primers do not appear flat to me, so in my opinion, I'd give it a full send.
 
The data on Hodgdon's website ranges from 4.7 to 5.1 grains for the +P pressure level for this bullet seated to 1.130" OAL. Your load should be fine.

Accurate No. 2 1.130"
4.7 1,105 35,600 PSI
5.1 1,151 38,300 PSI
 
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If the bottom case was shot in the Beretta, it looks normal. My 92FS does the same thing since new, 20+ years of shooting it.
 
Check the side of the cases--you'll likely see a faint line encircling the case where the case head meets the body and/or obvious bulging when starting into overpressure.
 
With autoloaders (unless you've used an inappropriate powder, which you haven't) my first indication of a too hot load is slide speed. Your cases should eject smartly, but not into the next county. A guy used to post here (sorry, forgot his nickname) that played with all sorts of crazy stuff, including modifying a 9mm and overloading like crazy under (somewhat) controlled conditions. Maybe some of the old timers remember him. He found slide speed to be the limiting factor. Two 1911s: One at a public range with a round the RO guessed was double loaded or more. Blew out the mag and did some cosmetic damage, but the pistol survived. The other had a cracked frame, not from overloads specifically, but from a steady diet of "on the edge" rounds.
 
A guy used to post here (sorry, forgot his nickname) that played with all sorts of crazy stuff,
Click to expand...

Ah, yes, that was 'Clark'. He would overload anything he got his hands on, the only pressure contributor he was wary of was "bullet pinch." That is a tight chamber neck, thick brass, or oversize bullet that would keep the case from expanding to release the bullet as pressure rose.
 
Starter said:
I use Berrys Bullets, 9mm, 115 grain, round nose double strike, .356 with Accurate #2 powder. The Accurate #2 load data indicated a range of 4.2 - 4.7.
Both casings in photo were loaded with 4.2 grains.
Click to expand...
What dimension are you using for C.O.L. (Cartridge Overall Length)?
 
You’ll find that the same breechface mark appears on all of your rounds fired from the Beretta 92 FS. If you examine your breech you’ll see that the area surrounding the firing pin is recessed. Even soft loads, under powdered loads, will produce the same mark…no way to prevent it.
When I started reloading, the Beretta 92 FS was my only 9mm pistol. I soon noticed that once I deprimed the offending cases the problem disappeared.
 
The appearance of the primer as any kind of 'pressure gauge' is urban myth.

You will not see primer deformation as a sure sign of overpressure until you are dangerously, insanely, over-pressure.

Source: Complete Guide to Handloading, Vol 2. Phillip B. Sharpe.

Sharpe shows examples of primers alongside pressure data. Phil Sharpe could be said to have invented the .357 Magnum.

Stick with published data.

I won't say you'll be safe, because we practice a sport where stuff blows up in your hand and near your face. But the probability of a negative outcome is dramatically reduiced by using published data, double checked with a second source.

Modern firearms in good condition can handle all published loads. But it never hurts to back off a grain or more from max.
 
Those primers look like they might be OK to me; that is no from excessive pressure. I'm thinking what appears to be cratering has to do with the firing pin hole in both firearms being slightly oversize allowing the primers to crater. I have a Remington M700 in 30-06 that will do that with even the mildest load possible; a 110 gr. cast bullet over 5.0 gr. of Unique that I use for plinking and small game. A look at the bolt face shows the firing pin hole has been chamfered and this is the cause. As I bought that rifle NIB, it had to have been done at the factory Just another thing you might want to look at.
Paul B.
 
The appearance of the primer as any kind of 'pressure gauge' is urban myth.
Click to expand...

The appearance of the primer as an indicator of pressure is not a myth. The myth is believing that it is a gauge. Its more like an indicator light. Like the "idiot lights" on your dashboard, it alerts you to an off standard condition, but does not (and cannot) tell you the amount or direction of the off standard.

Often a cratered or flattened primer indicates high pressure (but can't tell you how high) but not always. You can get cratered or flattened primers at normal pressure, due to various tolerances of the specific gun being fired. Primer won't tell you which, only tells you something isn't quite right.
 
The appearance of the primer as an indicator of pressure is not a myth. The myth is believing that it is a gauge. Its more like an indicator light. Like the "idiot lights" on your dashboard, it alerts you to an off standard condition, but does not (and cannot) tell you the amount or direction of the off standard.
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What's the difference between the primer used in 9mm (SAAMI Max 35000psi) and 9mm x23 Win (SAAMI Max 55000psi)?

Would max loads in both be expected to present the same primer appearance in spite of the 20000psi pressure difference?
 
I see high pressure signs in the primers of all the 9X23 Win ammo I shoot, and have had some pierced primers as well.
 
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74A95 said:
I see high pressure signs in the primers of all the 9X23 Win ammo I shoot, and have had some pierced primers as well.
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The general consensus among reloaders of the 9X23 is to use rifle primers. However, most think the Winchester factory rounds use mag pistol primers based on the look of the primer after firing. I have no hard facts to back that up.

I would always use a rifle primer considering the pressure involved.
 
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