Thread: Help - What is going on with these primers??

I took a couple pictures of both 32 and 40 grain superformance I've used in the past. Do these have any signs of pressure? Not really sure what I'm looking for...

Not so's I can see.

Pressure tends to flatten and /or crater the primers.




There are other signs but those are the 2 I know to look for, besides the holes in your norma cases.

Look at this image below which you posted, and compare to the primers on the picture you posted above: the rims of the primers are rounded still on the above picture, on the picture below here the primer is squashed completely flat at the back against the bolt face.

In the picture below, second one down shows the crater edge that @Max Headroom alludes to. In the pictures above about half of them show very mild cratering, the other half not, so some overpressure signs.

In the picture below, the fifth one down shows a crack at the bottom of the primer indentation where the primer wall has been thrust against and stretched over the firing pin, against the inertia of the firing pin. Primers 1, 3 and 4 show this effect more severely.

@Cordite Lol, I was thinking of more subtle signs....

Originally Posted by suthy

@Cordite Lol, I was thinking of more subtle signs....

Did you have any trouble lifting the bolt to extract the cases once you fired them?

Originally Posted by suthy

@Cordite Lol, I was thinking of more subtle signs....

You've got plenty to go by just looking for the obvious signs. (-:

@Cordite When I first saw your post I only saw the picture of the primers but it didn't come up with any text!I thought you were showing me the signs of pressure through pictures I had already posted...

@Max Headroom No problems with extraction that I noticed

Originally Posted by suthy

@Max Headroom No problems with extraction that I noticed

Ok . Stiff bolt lift is another sign of a hot round, now that I think about it.

Originally Posted by suthy

@Cordite When I first saw your post I only saw the picture of the primers but it didn't come up with any text!I thought you were showing me the signs of pressure through pictures I had already posted...

Hi, that makes sense. Sorry, just had to see the picture posted OK and then I edited it several times while comparing the different pics. A bit laborious but it was fun. Nice pics with a lot of good examples.

Originally Posted by Max Headroom

Ok . Stiff bolt lift is another sign of a hot round, now that I think about it.

And stiff upper lip is a sign of retention.... (-:

is there any chance that your chamber is slightly over length specs ? or these cases with the big FP indents are short - if the Sami 204 spec is a bit variable - don't know just putting it out there. Any signs of excessive case stretching / verging on head separation?

Originally Posted by Cordite

And stiff upper lip is a sign of retention.... (-:

I beg your pardon, sir?

A quick update on this. I spoke to the NZ supplier of this ammo and they were awesome. They asked for some photos etc so they could send them to the manufacturer and in the meantime they have got a box from a different batch on it's way down so I'll be able to test if it is batch related or not.

Hopefully I'll be able to post some results after next weekend.

@Moa Hunter I only just saw your post now. I did keep a case so I'll through up some pics. Don't really know what to look for however I did measure the case length and it measure 46.88mm long, internet tells me it should be 47mm?