Anyone pay much attention to cartridges fired in Glock 9mm and .40 S&W?

If primers were an indication of over pressure. Those would sure worry me.

Bushmaster wrote:

Primers are not an indication of pressure and should not be use as an indicator. Flattened primers (which is normal) indicate that you may have a bit of head space.

No disrespect oh wise sage and please forgive me for piping up but...

If you have a primer w/ zero radius left on it, yer OK?

A lot of things affect pressure, almost everything related to the cartridge and the gun affects pressure. Pressure is the result of a lot of factors and no two sets of factors are the same. Ever!

One of the only consistently readable tellers is the primer in most safe, normal published loads. It'll let ya know what's up long before something else does, in a lot of cases.

And the primer does the "in-out-in" thingy for most loads, regardless.

The primer is an awesome tell. If yer out of radius, yer most likely over the top, or on the cusp just asking for it, and need to back it down. And I don't care how accurate or fast it is. That's my advice to everyone FWIW.

All of my loads have a healthy radius left and are never anywhere near the MAX and they are safe and accurate and don't wear out the firearm.

I'll keep reading my primers, very closely, thank you very much.

p/s- were talking manly rifles here, not girly calibers like 9mm and 40 cal.

p/s- were talking manly rifles here, not girly calibers like 9mm and 40 cal.

HA HA Hahahahaha

God made them two fer the ladies that caint handle a .45

Bushmaster wrote:

Anyone pay much attention to cartridges fired in Glock 9mm and .40 S&W?

Hint...Hint.........They aren't round !!!



Stovey, shoot a Kahr PM40.............I bet it turns you into one of them their girlies !!!

Bushmaster wrote:

Anyone pay much attention to cartridges fired in Glock 9mm and .40 S&W? If primers were an indication of over pressure. Those would sure worry me.

Bushmaster, I don't reload my pistols so lack the experience to understand your comment. I have Glock 9's and 40's and just checked the primers. I didn't see any affects nor was I expecting to since they are load to 1/2 the pressure of my .270 Winchester.

What was I supposed to see?

Glocks tend to imprint the firing pin port [raised square].

chambered221 wrote:

Hint...Hint.........They aren't round !!!

OK, the primers on my 9mm and .40 cal are round. The firing pins in my Glocks are rectangular. Does your "They" refer to the firing pins?

Bushmaster wrote:

Glocks tend to imprint the firing pin port [raised square].

Why would I use primers on a 9mm or .40cal to read pressure in my pistols when they are loaded so low to begin with that pressure wouldn't affect the the primers?

My .270 Winchester, however, can be loaded for pressures above 60,000 psi which is the situation beind discussed. I've watched the primers begin to flatten as the powder charge is increased. I've witness the ridge form around the firing pin when I loaded 0.2 grains over max, a ridge that isn't there with the load at max or below. I agree that there can be other signs of over pressure, but I think in my situation with the .270 Win., the primer is my best indication without additional test equipment.

Signs of over-pressure:
Sticky bolt - you're pushin' your luck
Expanded case head - she's gonna blow!
Cases that last less than ten reloads - either too much resizing or too much pressure.
cratered primers - might be too hot or too light a load or your firing pin hole might be eroded and there is too much play between the pin and the hole for it.

It has been a long time since I have had any of these so I am out of practice and might have missed some but I know that if I run into any one of these I need to drop the load - if two show up at the same time I need to really drop it or check my scales.

also from past experience. my rifle doesnt like necksized rounds. it MAY have a bore /chamber slightly off line so I partialy resize and no probs. I dont know but could a similar condition be causeing the problems you are having?is this the rifle you rebedded on another post??? keep us posted you will be sure to sort it sooner or later.

Elvis wrote:

my rifle doesnt like necksized rounds. ... I dont know but could a similar condition be causeing the problems you are having?is this the rifle you rebedded on another post???

My reloads are neck-size only and are shooting the best in his rifle. Yes, this is the rifle I bedded in another post. Thought reading primers for pressure was a topic in itself so posted separately. Boy was that the situation!

For some good pictures of flattened primers & other issues. go here: stevespages.com/diagno...blems.html

Bushy, I don't necessarily agree with you, but I don't disagree either.......but I did understand your analogy with the Glunks I mean Glocks !!!


Slim, the same principles apply to both pistol and rifle primers. The controlling factor is the thickness of the cup and the amount fire they have.

slimjim wrote:

Bushmaster wrote: Glocks tend to imprint the firing pin port [raised square]. My .270 Winchester, however, can be loaded for pressures above 60,000 psi which is the situation beind discussed. I've watched the primers begin to flatten as the powder charge is increased. I've witness the ridge form around the firing pin when I loaded 0.2 grains over max, a ridge that isn't there with the load at max or below. I agree that there can be other signs of over pressure, but I think in my situation with the .270 Win., the primer is my best indication without additional test equipment.

I think you are on to something but what I noticed in your excellent photo's are the marks on the brass that circumference the base this can also be a sign that your maxing out depending on how shiny they are. This is a mark left by raising the bolt on a cartridge that isn't springing back from the initial expansion or pressure spike,