Flattened primers

pinne65 · Jun 3, 2012

Can someone who knows what flattened primers look like take peek and tell me if any of these are?

I'm working up a load for Hornady XTP HP 180gr using Blue Dot. These pics shows loads 10.9gr - 10.0gr from left to right.

accessbob · Jun 3, 2012

Looks just like the firing pin on the Smith and Wesson Sigma SW9F we just sold. It has a flat firing pin with a point but the point is not round so to speak it is rounded at the tip, which gives the round impression just like it is there but it also is flat as well and puts the pin mark just like you have there.

pinne65 · Jun 3, 2012

I'm using a Glock 20. Almost all my cases look like that. Even factory. Guess I need to buy a box again...

accessbob · Jun 3, 2012

pinne65 said:
I'm using a Glock 20. Almost all my cases look like that. Even factory. Guess I need to buy a box again...

Well, it looks like your firing pin is quite like the Sigma SW9F. This is your firing pin:

pinne65 · Jun 3, 2012

Yea, after some quick online research it seems like it's the so called "Glock mark". Yet to be confirmed though...

BANE · Jun 3, 2012

+1 Glock Mark :s0155:

HappyRoman · Jun 4, 2012

yes Glock mark; Primers look fine= fired. These are not flattened enough to cause me any worries.

deadshot2 · Jun 4, 2012

When I use primers as a pressure indicator, I look to the edge of the primer. If it still has some radius to it pressures aren't excessive, all other things being equal. When the primer edge takes a square shape and fills any remaining gap in the primer pocket that "CAN" be a sign of excessive pressure. The reason I say "CAN" is that some primers are extremely soft and that's a normal shape for a load that's just reached it's max workable pressure.

Something else to pay attention to is the case itself. If you start seeing marks on the side of the case that look like scatches from case head to about half way to the mouth, you may have exceeded safe pressures by a bunch. The case is stretched into a chamber that has expanded somewhat and then forced out during the ejection process, leaving these drag marks. Very noticeable.

Another way to check for excessive pressure is to measure the case head before shooting and after. Measure just above the extractor groove and if it expands more than .0005", then "turn down the wick a little".

pinne65 · Jun 4, 2012

The brass looks ok to me. No marks yet. Since it'll now be the 2nd load with it I will back off a little any way. I'm just curious deadshot, what kind of calipher do you have that does 1/10000s? Mine just does 1/1000s and I'm not really happy with it, considering getting a new one...

deadshot2 · Jun 5, 2012

pinne65 said:
The brass looks ok to me. No marks yet. Since it'll now be the 2nd load with it I will back off a little any way. I'm just curious deadshot, what kind of calipher do you have that does 1/10000s? Mine just does 1/1000s and I'm not really happy with it, considering getting a new one...

You really won't get the fine accuracy to measure below .0005" with a caliper (Unless you want to spend big bucks). You need a good old-fashioned micrometer with the cast "C-Frame". There are all kinds of "Big Name Brands" available but will set you back a fair amount of change.

Here's one that works great and is accurate to +/- .00015". More than enough for measuring case head expansion.

Amazon.com: IP 54 DIGITAL ELECTRONIC OUTSIDE MICROMETER 0-1" LARGE LCD with bonus ball attachment: Home Improvement

Under $50 and more than adequate for reloading details. Also "Digital" for those that are "Vernier Challenged" like myself

Keep the Caliper. It's more than accurate enough for OAL measurements.