Primer fit

jag2 · April 26, 2012, 10:04 PM

I think you can see the difference, its hard to photograph. The primers in the top row look like they fit perfectly in the pocket with almost no gap. The bottom row shows a slight one. With just my eyes I see virtually no gap, I guess it shows more in the picture because of the lighting. If it was wood it would be like you pounded a dowel in a very tight hole and cut it off flush. I never buy factory ammo but it looks like two different styles. Is one of these a higher priced round? Does all factory ammo look like the top row and reloads like the bottom row? I pick up a lot of range brass in addition to my own reloads, I'm sure mine never looks that tight. Just curious.

m&p45acp10+1 · April 26, 2012, 10:11 PM

There are more variables than I care to even begin to attempt to list. Though simiauto fired brass can be tricky due to unsupported chambers, and the firing pin when the brass is extracted. They all look fine to me by the way.

jag2 · April 26, 2012, 10:31 PM

Maybe I didn't explain my question enough. Every brand of primer I've loaded, and I think that is most all, have a rounded base so they look like the bottom row whereas the the top row looks like they are custom fitted and their edge would sharp, not rounded. Does that make sense? I'm sure they all worked fine, just wondering what the difference is.

hk33ka1 · April 26, 2012, 10:59 PM

I think all the primers have a rounded edge, but some after firing flow to fill out the slight space in the pocket while tight against the bolt face.

That said they all look good.

mrawesome22 · April 26, 2012, 11:24 PM

Umm... what?

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PA-Joe · April 27, 2012, 07:20 AM

That is what we call flattening. It may be an indication that you are getting a little hot or getting uneven powder drops. They don't look bad though. Are the new ones in the box also flat or do they have a round edge.

Rangefinder · April 27, 2012, 09:10 AM

It's flattening due to higher pressure. You're fine--but check your measure. If you start seeing the primer strike dimpling shallow or cratering, you're pressure is going higher than it should and you start risking damage.

jag2 · April 27, 2012, 10:07 AM

I am aware of the term flattening but haven't seen it before or even thought about it. I guess I associate it more with high powered rifle rounds. I don't load anywhere near max so I doubt these were mine. As I said I do pick up a lot of range brass and I have very few of the flattened ones so it must have someone around me or that was there earlier. If a couple of you think that is what it is thats good enough for me. Glad I asked, learned something new.

serf 'rett · April 27, 2012, 10:26 AM

Looks like flattening to me.

When testing and "ladder" of pistol loads, I set up a brass catcher so I can inspect the primers as I'm working my way up from lowest to highest charges. Since I'm using fairly hard primers, like CCI, Wolf, Tula, I really pay attention when I see the primers starting to flatten. If the primer starts to crater; i.e., flow back into the gap between the firing pin and firing pin channel...well, I may be whacking the rest of those rounds apart when I get back home.

Wyoredman · April 27, 2012, 10:36 AM

Flattening of primers occurs in some of my handguns with factory loads. I always assumed it was from a bit of extra chamber space and the primer moving a bit before the case had a chance to grip the chamber wall. The firing pin stike moves the case forward, ignition moves the primer rearward, the case recoils against the bolt face reseating the prime but also flattening it a bit. Tell me if I'm wrong here?

Rangefinder · April 27, 2012, 11:59 AM

That is a very good possibility as well ^^^^

It only takes a chamber a couple thousandths long to do that.

serf 'rett · April 27, 2012, 12:16 PM

Flattening can occur with factory loads or case movement. My reloaded primers are inspected at home using 20X loupe. The "eyeglass" really picks up small variations.

jephthai · April 27, 2012, 12:48 PM

I was concerned when I saw flattening on SSA factory loads for my 6.8spc, and the 68forum folks said that SSA uses softer primers. So there's a possibility as well.

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bfoosh006 · April 27, 2012, 03:04 PM

"I don't load anywhere near max so I doubt these were mine."

That is your answer. Hotter rounds will show "squared edge primers" from incresed pressure, while mild loads usually don't.

Shootest · April 27, 2012, 04:06 PM

Also consider that flattening can occur even with light loads if the primer pocket becomes loose from multiple loadings

April 26, 2012, 10:11 PM	#2
m&p45acp10+1 Senior Member Join Date: May 3, 2009 Location: Central Texas Posts: 3,930	There are more variables than I care to even begin to attempt to list. Though simiauto fired brass can be tricky due to unsupported chambers, and the firing pin when the brass is extracted. They all look fine to me by the way. __________________ No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.

April 27, 2012, 09:10 AM	#7
Rangefinder Senior Member Join Date: August 4, 2005 Posts: 2,017	It's flattening due to higher pressure. You're fine--but check your measure. If you start seeing the primer strike dimpling shallow or cratering, you're pressure is going higher than it should and you start risking damage. __________________ "Why is is called Common Sense when it seems so few actually possess it?" Guns only have two enemies: Rust and Politicians.

April 27, 2012, 10:26 AM	#9
serf 'rett Senior Member Join Date: June 25, 2009 Location: Stuttgart, AR Posts: 1,569	Looks like flattening to me. When testing and "ladder" of pistol loads, I set up a brass catcher so I can inspect the primers as I'm working my way up from lowest to highest charges. Since I'm using fairly hard primers, like CCI, Wolf, Tula, I really pay attention when I see the primers starting to flatten. If the primer starts to crater; i.e., flow back into the gap between the firing pin and firing pin channel...well, I may be whacking the rest of those rounds apart when I get back home. __________________ A lack of planning on your part does not necessarily constitute an emergency on my part.

April 27, 2012, 10:36 AM	#10
Wyoredman Senior Member Join Date: September 6, 2011 Location: Wyoming Posts: 1,352	Flattening of primers occurs in some of my handguns with factory loads. I always assumed it was from a bit of extra chamber space and the primer moving a bit before the case had a chance to grip the chamber wall. The firing pin stike moves the case forward, ignition moves the primer rearward, the case recoils against the bolt face reseating the prime but also flattening it a bit. Tell me if I'm wrong here? __________________ Go Pokes! Go Rams!

April 27, 2012, 11:59 AM	#11
Rangefinder Senior Member Join Date: August 4, 2005 Posts: 2,017	That is a very good possibility as well ^^^^ It only takes a chamber a couple thousandths long to do that. __________________ "Why is is called Common Sense when it seems so few actually possess it?" Guns only have two enemies: Rust and Politicians.

April 26, 2012, 10:31 PM	#3
jag2 Senior Member Join Date: June 30, 2009 Location: dallas Posts: 773	Maybe I didn't explain my question enough. Every brand of primer I've loaded, and I think that is most all, have a rounded base so they look like the bottom row whereas the the top row looks like they are custom fitted and their edge would sharp, not rounded. Does that make sense? I'm sure they all worked fine, just wondering what the difference is.

April 26, 2012, 10:59 PM	#4
hk33ka1 Senior Member Join Date: April 20, 2010 Posts: 275	I think all the primers have a rounded edge, but some after firing flow to fill out the slight space in the pocket while tight against the bolt face. That said they all look good.

April 26, 2012, 11:24 PM	#5
mrawesome22 Senior Member Join Date: November 9, 2005 Location: Ohio, Appalachia's foothills. Posts: 3,779	Umm... what? Sent from my Wildfire S using Tapatalk 2

April 27, 2012, 07:20 AM	#6
PA-Joe Senior Member Join Date: June 9, 2010 Location: NEPA Posts: 909	That is what we call flattening. It may be an indication that you are getting a little hot or getting uneven powder drops. They don't look bad though. Are the new ones in the box also flat or do they have a round edge.

April 27, 2012, 10:07 AM	#8
jag2 Senior Member Join Date: June 30, 2009 Location: dallas Posts: 773	I am aware of the term flattening but haven't seen it before or even thought about it. I guess I associate it more with high powered rifle rounds. I don't load anywhere near max so I doubt these were mine. As I said I do pick up a lot of range brass and I have very few of the flattened ones so it must have someone around me or that was there earlier. If a couple of you think that is what it is thats good enough for me. Glad I asked, learned something new.

April 27, 2012, 12:16 PM	#12
serf 'rett Senior Member Join Date: June 25, 2009 Location: Stuttgart, AR Posts: 1,569	Flattening can occur with factory loads or case movement. My reloaded primers are inspected at home using 20X loupe. The "eyeglass" really picks up small variations. __________________ A lack of planning on your part does not necessarily constitute an emergency on my part.

April 27, 2012, 12:48 PM	#13
jephthai Senior Member Join Date: July 5, 2007 Posts: 463	I was concerned when I saw flattening on SSA factory loads for my 6.8spc, and the 68forum folks said that SSA uses softer primers. So there's a possibility as well. Sent from my DROID4 using Tapatalk 2

April 27, 2012, 03:04 PM	#14
bfoosh006 Senior Member Join Date: February 17, 2009 Posts: 1,089	"I don't load anywhere near max so I doubt these were mine." That is your answer. Hotter rounds will show "squared edge primers" from incresed pressure, while mild loads usually don't.

April 27, 2012, 04:06 PM	#15
Shootest Senior Member Join Date: February 9, 2011 Location: Just outside Cleveland, Ohio Posts: 722	Also consider that flattening can occur even with light loads if the primer pocket becomes loose from multiple loadings __________________ The private ownership of firearms is an American Heritage. Anyone who disputes that is Anti-American and unpatriotic. NRA Life Member