9mm pressure signs, how much is too much?

[dieselrealtor]

*Any data posted here is for academic and discussion purposes only, not recommended for load data. DO NOT exceed published load data and follow safe reloading practices*

Seems a lot of the factory 9mm brass I see has pressure signs, cratering, flowing, etc.

Experienced reloaders, what do you consider acceptable?

 

[Cynical]

*Any data posted here is for academic and discussion purposes only, not recommended for load data. DO NOT exceed published load data and follow safe reloading practices*

Seems a lot of the factory 9mm brass I see has pressure signs, cratering, flowing, etc.

Experienced reloaders, what do you consider acceptable?

I think by the time you see pressure signs in pistol rounds its probably too late. A chrony will help when starting to see if velocity is close to published data, if the velocity is way higher so is the pressure. To your point, Ive seen factory 9's and .40's that looked cratered but sized them and moved on.

 

[Trapper Jim]

Depends on the gun. Unsupported chamber = less pressure threshold.

Lower cost or streamlined manufacturing = less pressure threshold.

Until the 80’s we did not see the bay floors littered with blown cases as we do now.


Flattened primers back off. Ruptured cases means injury may be next.

That is all.

 

[DadSmith]

*Any data posted here is for academic and discussion purposes only, not recommended for load data. DO NOT exceed published load data and follow safe reloading practices*

Seems a lot of the factory 9mm brass I see has pressure signs, cratering, flowing, etc.

Experienced reloaders, what do you consider acceptable?

You start seeing the primers flattening time to back off to a lesser load.

Unsupported chamber such as my Glock 20 had in 10mm you'll get Glock smiles which ruin the cases, but you still haven't gotten anywhere close to maximum pressure for the 10mm. I know you are shooting 9mm. I just through that in as a reference. I imagine some 9mm chambers are just as bad.




This is caused from unsupported chambers.

Here is a decent video on primers.

 

[natdscott]

Some tried to get 9mm to make Major. Ironed off the headstamps from new brass.

Or at least, that's the legend.

 

[Trapper Jim]

Some tried to get 9mm to make Major. Ironed off the headstamps from new brass.

Or at least, that's the legend.

Yep because of USPSA Major scoring rules. But in fully supported all steel guns. 9x21 could make major but at a cost.

 

[two70]

I think by the time you see pressure signs in pistol rounds its probably too late. A chrony will help when starting to see if velocity is close to published data, if the velocity is way higher so is the pressure. To your point, Ive seen factory 9's and .40's that looked cratered but sized them and moved on.

This. I forget the exact number but pressure signs don't normally start showing on the primer until past normal rifle pressures. Standard maximum 9mm pressure is around half the upper end of standard rifle maximum pressure so by the time pressure signs are showing on the primer, the pressure is well above 2X the max and likely approaching 3X.

 

[Aszerigan]

You start seeing the primers flattening time to back off to a lesser load.

Unsupported chamber such as my Glock 20 had in 10mm you'll get Glock smiles which ruin the cases, but you still haven't gotten anywhere close to maximum pressure for the 10mm. I know you are shooting 9mm. I just through that in as a reference. I imagine some 9mm chambers are just as bad.

View attachment 306413
View attachment 306412

This is caused from unsupported chambers.

Here is a decent video on primers.

Those look like some very, VERY hot loads from a 10mm. I’ve seen quite a bit of bulged brass but nothing that severe.

Or 220gn Steel heads?

 

[natdscott]

Yep because of USPSA Major scoring rules. But in fully supported all steel guns. 9x21 could make major but at a cost.

Well, and as has been said in other shooting comps: "My brass will hold once."

I guess, if you trust your platform, and load carefully, it doesn't much matter, since the brass that hits the ground stays on the ground in a lot of the pistol sports.



...is everybody listening, who loves to load in "cheap" range pickup?

 

[DadSmith]

Those look like some very, VERY hot loads from a 10mm. I’ve seen quite a bit of bulged brass but nothing that severe.

Or 220gn Steel heads?

Actually those might be I got them from the internet.

My Glock 20 10mm was doing similar smiles to the cases with 10% less than maximum load of course I was using good old 800x 10.6gr with 155gr XTP bullets. 1457fps in the glock 20 original barrel.
I tested upto 11gr, and that's when the Glock smiles started.
Reason I like 800x is because it keeps the pressure on the low side.
My understanding they aren't making it anymore and that saddens me. It was one of my favorite powders for several handgun calibers.
Same load in the 1911 10mm had no problems, because it had much better chamber support.

 

[ECS686]

You start seeing the primers flattening time to back off to a lesser load.

Unsupported chamber such as my Glock 20 had in 10mm you'll get Glock smiles which ruin the cases, but you still haven't gotten anywhere close to maximum pressure for the 10mm. I know you are shooting 9mm. I just through that in as a reference. I imagine some 9mm chambers are just as bad.

View attachment 306413
View attachment 306412

This is caused from unsupported chambers.

Here is a decent video on primers.

This is what got a lot of Glock shooters in trouble with 40. All those KB pics of Glock 40 cals wasn’t over pressure rounds or guns magically firing out of battery it was reloaded reloading their brass way too many times.

Even if they full length resized (as they should have been) the brass still got weaker each time so anything over 2 or 3 times…look out!

 

[DadSmith]

This is what got a lot of Glock shooters in trouble with 40. All those KB pics of Glock 40 cals wasn’t over pressure rounds or guns magically firing out of battery it was reloaded reloading their brass way too many times.

Even if they full length resized (as they should have been) the brass still got weaker each time so anything over 2 or 3 times…look out!

My 1911 10mm has shot many x reload brass without problems.
I've had to toss a few because the walls were getting to thin. I do believe a lot if problems can be solved with proper chamber support.

 

[ECS686]

My 1911 10mm has shot many x reload brass without problems.
I've had to toss a few because the walls were getting to thin. I do believe a lot if problems can be solved with proper chamber support.

I ran a Glock 35 in 40 for ISPSA when there were only 2 divisions. I ran a Para P16 in 40 before that. Back then we picked up our brass and a couple times my reloads for the para wouldn’t chamber because unbeknown to me it was Glock brass. This was late 90’s before I really learned about full length resizing importance.

I moved to the Glock them resized he “Glock Bulege” out and never had any issues running them in either.

I followed the “KB” issue won Glock 40 but never worried because from all the pictures it seemed they were all ruptured cases at the back. That told me in all likelihood it was folks too cheap to get new brass OR the ones that double charge and blame the gun.

My personal practice was if buy loads factory shoot it then at the second reload or 3rd time the brass was fired it was disposed of.

Why I quit picking up brass that I wasn’t 100% sure was mine.

 

[DadSmith]

I ran a Glock 35 in 40 for ISPSA when there were only 2 divisions. I ran a Para P16 in 40 before that. Back then we picked up our brass and a couple times my reloads for the para wouldn’t chamber because unbeknown to me it was Glock brass. This was late 90’s before I really learned about full length resizing importance.

I moved to the Glock them resized he “Glock Bulege” out and never had any issues running them in either.

I followed the “KB” issue won Glock 40 but never worried because from all the pictures it seemed they were all ruptured cases at the back. That told me in all likelihood it was folks too cheap to get new brass OR the ones that double charge and blame the gun.

My personal practice was if buy loads factory shoot it then at the second reload or 3rd time the brass was fired it was disposed of.

Why I quit picking up brass that I wasn’t 100% sure was mine.

Oh yeah the rupture cases is definitely pursuing maximum velocity no doubt.
You're not going to have those problems running normal pressure rounds in a Glock barrel or in any other unsupported chamber barrel.
Now 10mm actually can handle higher pressure than a 44mag. 10mm 37500psi 44mag is 35000psi
Chasing those full power nuclear load 10mm loads with an unsupported chamber is bad idea.
That's why I had to back off to what my Glock 20 barrel would shoot without destroying my brass.
Thankfully you can now buy barrels with fully supported chambers, or firearms such as 1911's that do.

I full length size all my brass. Have done so for many decades.
I learned back when I had a 357mag shooting full power loads I ran into the same problem you had with your range brass 40 S&W. Except not fitting into the cylinder.
This was years ago when I first started reloading, and I couldn't just run a online search. I had to talk to other reloaders, and learn.

 

[Dean C.]

CZ's 9mm Major recipe , it works very very well. Only shoot in fully supported guns and only shoot the brass once. Once fired brass at an absolute minimum IMHO, knew a guy in USPSA that used to test his hand loads with an MP5 and an oven mitt