Are These Primer Indentations Normal?

C

Captains1911

New member
I am getting these unusual rectangular shaped primer indentations with a particular type of 9mm ammo. Two different Glocks create the same marks with this anmo only. Is this anything to be concerned about?

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Are the primers not fully seated? It looks as though the primer is not properly seated and the breechface is only making contact with the face of the primer as the slide goes into battery, leaving an impression from the rectangular firing pin hole in the primer as the slide slams home.
 
Those are standard Glock indents. Both Glock and M&P (tear drop shape) have a distinctive pattern.


Here's a pretty standard Beretta next to a Glock.


Dave
 
It seems odd that this would only happen with one brand of ammo, though, but listen to the people who shoot Glocks. I don't think I've fired my G17 once in the last four years.
 
I've seen it with every ammo I've used but I guess a really hard primer could have a much lighter indent.

Dave
 
Lock slide back on Glock. Look at breechface. See the rectangular
striker hole? If the primer bump is more pronounce with some brands of ammo, they either have softer primers or higher pressure.

ETA--You keep messin' with that Tupperware, your are going to have to change
your username!:)
 
For as long as I have been shooting Glocks, I have never noticed this. I guess I need to pay better attention.

ETA: I created that screen name long ago before I knew any better. ;)
 
I'm new to Glocks and only have a few hundred rounds through mine--so far none of my primers show that. However, I have recently ordered a couple of custom barrels and noticed that the chamber tolerances are more "loosey-goosey" with the Glock barrel in comparison--my theory there is a possibility there will be more issues with case moving when sealing upon ignition. But I could be totally wrong too as that's just a guess. (notice how the striker indentation is more elliptical than round).
 
someone can give you a definition to as why it happens, but some types of ammo whether it's stronger or weaker I cannot remember, but it causes the firing pin to wipe down the primer as it's being ejected. lots of people have asked the same question. the consensus has always been, it's normal....carry on. not all will do it. I have seen it mostly of 45's for whatever reason
 
I am getting these unusual rectangular shaped primer indentations with a particular type of 9mm ammo. Two different Glocks create the same marks with this anmo only. Is this anything to be concerned about?
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Absolutely normal with Glocks. You've never noticed this before?
 
Absolutely normal with Glocks. You've never noticed this before?
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Honestly, no I have not noticed it in almost 10 years of shooting Glocks and currently owning 4. I don't reload either, otherwise I'm sure I would have. This particular anmo was very inexpensive, and so I examined it a little closer.
 
All my Glocks do that. Ive found a lot of brass like that too, which makes it pretty easy to tell what gun they came from.

I believe its just the result of the primer being pushed into the breech face under pressure on firing, fire forming the primer into the breech face/firing pin hole. As was mentioned, some rounds use softer primers, or have more pressure, or both, and you get varying examples of it.
 
Would that be Freedom Munitions New ammo? I know the cases are a little funky inside and you may be seeing a pressure issue. FWIW, I shoot FM reloads all the time and have never had a problem.
 
Saw my first Glock in 1989, a G17.

I have never in my life seen brass ejected from any Glock that didn't look like that. Always, any caliber, any model. Though I will admit that I have shot the G42 but didn't think to look at that brass.

That is -more- than normal. I'd wig out if it didn't look like that.
 
Saw my first Glock in 1989, a G17.

I have never in my life seen brass ejected from any Glock that didn't look like that. Always, any caliber, any model. Though I will admit that I have shot the G42 but didn't think to look at that brass.

That is -more- than normal. I'd wig out if it didn't look like that.
__________________
Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.
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Now you got me worried : ) I'm in the middle of reloading a couple hundred for my Glock 20 and just took a magnified look at the spent primers--a few of them do in fact have a slight rectangular ghost image of the breech plate/striker face plate that is barely perceptible--but nothing as pronounced as what's shown above. On the other hand--I haven't fired any full-power hot loads either--so this might change. Currently working on upgrading barrel, springs etc before going out into full-power territory.
 
Would that be Freedom Munitions New ammo? I know the cases are a little funky inside and you may be seeing a pressure issue. FWIW, I shoot FM reloads all the time and have never had a problem.
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Yes, Freedom Munitions RN New.
 
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