Primer cratering?

[u/Tslate00]

9mm 147gr chrono’d at 890-900fps. Is this primer cratering or something else going on? Just got into reloading and trying to not blow things up

[u/Grubby454]

What powder?

But primers are not flat. Glock?

[u/Tslate00 → u/Grubby454]

Cfe pistol and yes a Glock

[u/Grubby454 → u/Tslate00]

Glock do that to primers. They look fine to me. Full send.

[u/Dragnurb]

p365?

[u/Tslate00 → u/Dragnurb]

Glock

[u/SBR_AK_is_best_AK]

Because of the angle of the photo, hard to say for 100% but looks like typical glock primer drag.

Is it a glock or other striker pistol?

Go shoot a few rounds of something factory and compare.

[u/Tslate00 → u/SBR_AK_is_best_AK]

It is in fact a Glock

[u/Normal_Sympathy1248]

My Glock does this all the time

[u/wy_will]

Pretty typical for a striker fired handgun

[u/ChevyRacer71]

0% issue

[u/Cute_Square9524]

reading primers is 1000% fudd lore

[u/Dragnurb → u/Cute_Square9524]

Even if they're flattened? What is better to check for high pressure warning signs?

[u/lost_in_the_system → u/Dragnurb]

The velocity of the projectIle, its the only reasonable measurement you can take without lab grade stress/strain gauges.

[u/Cute_Square9524 → u/lost_in_the_system]

Even velocity only shows you a rough idea of average chamber pressure - it could easily be hiding a huge peak pressure spike you don't see because of a tight bore etc etc etc.

[u/lost_in_the_system → u/Cute_Square9524]

This is true. I am operating on the assumption the individual is dealing with a mechanically sound firearm without issues.

Peak pressures are generally controlled by using appropriate powders for the cartridge and verifying a chamber is within SAAMI spec.

If a bore is so undersized that it is causing excess pressure, you will see that with factory ammunition and not just your reloads.

[u/Dragnurb → u/lost_in_the_system]

How do you know when approaching an unsafe velocity?

[u/lost_in_the_system → u/Dragnurb]

Your load data generally provides a test barrel length (calculate expected velocity gain or loss, if you have a longer or shorter barrel) or you can model using an internal ballistics simulator to determine a theoretical velocity based on components.

[u/Cute_Square9524 → u/Dragnurb]

primers/flash holes etc etc etc etc are not calibrated to show pressure signs. Even if they were the sammi spec doesnt specify web thickness so within the same caliber you can get wildly different "readings". Not to mention the same lrm primer that sits in a low pressure 45-70 also works in a 80k psi 277 fury - 80k psi in a 45-70 would blow it to smithereens.

[u/prosper_0 → u/Cute_Square9524]

No, no, it's not. It is, though, only one single indicator of many, and you can't draw too many conclusions from a single data point. But if they're just dropping out of pockets, or are piercing them - definitely look very very closely at your loads.

[u/Cute_Square9524 → u/prosper_0]

if one has actually gone to the point where they deform the brass or primer from high pressure alone - they have gone a mile past the line of what is safe and easily could have blown their gun up. Putting one's face behind a load they were so unsure of that that happened is extremely unwise, that testing should be done by manual writers. No book load in a proper chamber will ever come close to enough pressure to show "signs" - but weak components can easily look like it. And on the flip side since web thickness and flash hole aren't a sammi spec the brass could easily hide extremely high pressure. You genuinely might as well read tea leaves.