Pressure indicator?

[kxkid]

On the left is my load of 4.0 grn of wst over a 122 silver state I powder coated and then sized to .3576 seated to 1.07. All pics are one of my reload cases next to a mke factory 9 load. First is my gen 4 glock 17, then xd9 4", followed by a metro arms American classic 5". Are these looking close to being over I am looking at going down to 1.06-1.05 to not have chambering issues with the xd9 since they are pc'd.ImageUploadedByTapatalk1422917928.875802.jpgImageUploadedByTapatalk1422917966.515576.jpgImageUploadedByTapatalk1422917972.850345.jpg

[Longshot4]

It has been about 10 years since I have loaded 9mm. The smearing of the primer pocket is similar to a previous post. You might try searching primer...
As far as high pressure signs the edges of the primers are nice and round so I would not except a high pressure issue. If the edges of the primers were flat I would back off at least until the primers start rounding off. There are lots of pistolaros out there that should be able to give you better verification.

[Clark]

When I started handloading 15 years ago I did a work ups in 9mm.
I am now convinced that when the primer are gone, stop working up.
In my first work up I did not stop until the gun was wrecked. In the pic, the case on the left, destroyed the extractor and blew the innards out of the magazine. I should have stopped long before the one on the right.

But you still have your primers. That's encouraging.

[jdscholer]

I've heard a few guys say that with semi auto handguns, the first sign of high pressure is often a broken gun. Sometimes the "pressure signs" that we look for are kinda hoaky at best, and not very consistant from gun to gun.

One brand of primer might look like a real high pressure indicator, and another might show nuthin with the same load.

Some guys use their chrony as a pressure indicator, stating that for a given pressure you should achieve a certain velocity. I can see some weakness with that method.

Hmmm. I'm probably not telling you anything you want to hear. Be careful. jd

[kxkid]

Everything you all have told me is the same I have found doing research since posting this. Thank you all

[44 AMP]

Cratered primers is a pressure sign, but it can also happen for other reasons at safe pressures. Any additional pressure signs (like the edge of the primer flowing to meet the edge of the brass, "flattened primers") is a clear STOP sign.

Some brands of primer are softer than others, meaning at the same pressure, brand A might show nothing and brand B might show craters, etc.

Also, every gun and ammo combination is an individual. While most behave about the same, some will be much different.

[Longshot4]

Now after thinking about the primer pressure signs. I don't know for sure but. I would not be surprised if a semi auto would not show much sign do to the pressure is bled off when the bolt moves. Where as a revolver or bolt would hold pressure do to it being locked in place causing primers to flow easer. What do you think about?

[44 AMP]

a semi auto would not show much sign do to the pressure is bled off when the bolt moves. Where as a revolver or bolt would hold pressure do to it being locked in place causing primers to flow easer. What do you think about?

No, that's not what happens. The pressure is "bled off" when the bullet leaves the barrel. The breechface of a semi auto never moves in relation to the barrel until after this has happened.

Keeping in mind we are talking about very small areas and very short times.
No matter the action, the base of the cartridge is not normally a crush fit against the boltface. SO even locked in the chamber, there is a small space for movement backwards.

When the firing pin strikes the primer, #1 it pushes the case forward up against whatever sets the headspace (maybe adding a tiny bit more room between the case head and the bolt face. The primer detonates, generating a small amount of pressure, not a lot, but enough to push the primer backwards, sometimes to the full limit it can go, hard up against the bolt face.

The powder burns raising full pressure, which pushes in all directions. This pushes the case back against the bolt face, re-seating the primer.

At the same time, that full pressure is also pushing against the primer cup metal (though the flash hole), and the cup is much thinner than the case. There is a matter of timing involved, but basically, if the pressure is too high the cup sticking out of the case will be bulged (flow) just before the case head moves back reseating it. This is what leave the "flattened" primer with the primer cup all the way out to the edge of the primer pocket.

You can see this easiest in a revolver. You can do it yourself at home(), and all it will cost you is a few primers. Prime some cases, then fire them. You'll see primers backed out, maybe cratered, maybe even jamming against the recoil shield dragging or even jamming the revolver!

No powder,, nothing but the primer, and this is what happens. Now, do it again, except this time, add a snug paper wad or a wax "bullet". No powder.
Fire them, and things will be normal. This is because the added "backpressure" in the case because it has a wad/bullet lets the pressure from the primer "re-seat" the primer in the case.


hope this helps..

[Longshot4]

Thank you for your clear detailed explanation of primer pressure.

[totaldla]

First, always follow published load data. Second, your primer looks fine - you are not over-pressure. Lastly, consider investing in a chronograph as it will give a second data point.

[kxkid]

I can't find published data for 9mm and wst, just started at 3.5 and read what other people were at with it and went from there. I know I need to get one just don't have the money for one right now. Reason I am using wst is because 3 years ago I got a hold of 40 pounds of it so trying to find a load for 9mm with the 125 grain lead, which I have for the silver state pcd and the 125 Lee ones I pour. Just need to get something for 38 and 357 with the 125, and figure out a 40 load that is a decent light recoil load. Thank you all for your help.

[44 AMP]

What happens when there is no data to be found for what you have and want to use?

"You're off the map, mate, there be dragons here!"

Tickling the dragon is how we got our first data to begin with. CAREFUL, methodical testing. Changing only one variable at a time. Remember you're working with fast powders and small cases (handgun), and a wrong step can mean a damaged handgun and a damaged shooter.

watch for the usual pressure signs, and track case head expansion. Seating depth can make several thousands of pounds pressure changes in a tiny fraction of an inch. These and many other things, watched carefully, and the willingness to stop at a sane point will keep you safe.

Good Luck!

[Wreck-n-Crew]

I can't find published data for 9mm and wst,

They stopped publishing data for 9mm and WST. You might find it in an older publishing. Even though WST formula has not changed I would still remember that sometimes powders do and if you use old data for an old formula you can get into trouble.

[jepp2]

The challenge with loading the 9mm, is bullet seating depth. This cartridge "can" be very sensitive to minor changes in bullet seating depth. And the OAL can vary from 1.060" to 1.169" with as little as 0.020" being a great load or overpressure.

My suggestions:

- when you select a load, if you aren't using the exact same bullet as the load listed, then calculate the bullet seating depth and use that same value for your loads to start with. If you don't understand the difference between OAL and bullet seating depth, ask questions!

- with experience you will learn the signs of increasing pressure in your pistol. For mine, I notice changes in the chamber imprint on the exterior of the fired casings, the ejection patten and obviously velocity. Primers are a really unreliable signs of pressure. Might work today with brand X and not tomorrow with brand Y.

- you can't go wrong with starting low, so low the pressure will not cycle the slide, and start increasing powder loading OR reducing OAL and thus increasing bullet seating depth.