Ring around primer pocket?

[BenKK]

These photos are of once-fired Lapua .22-250 brass.

I loaded them a few years ago with 35 grains of 2208 and 55 grain TSXs.

Something was wrong. Difficult bolt lift and speeds over 3700fps.

A new barrel had recently been installed.

I took the rifle to another gunsmith, and he could immediately tell, using his gauges, that the headspace was wrong. He fixed the problem and it has been going well since then.

Today I went to get these brass pieces to reload, but aside from flattish primers (understandable) I noticed a ring that I don’t recall being on the new brass.

I’m wondering what this means and if the brass is safe to reuse?

 

[Dr Ray]

Maybe slight primer leak
Back off powder 1-2 grains
See if that solves problems

 

[Mekaniks]

I wouldn't reuse them

 

[sestoppelman]

Not sure what you are referring to but if you mean the slightly recessed ring around the circumference of the primer, that's normal for Lapua brass.

 

[larry4831]

It also looks like from the picture that the primers are backing out of the case a bit. I’d back off 2 grains and see if that helps. But I would start with new brass not the old brass that’s ringed

 

[sestoppelman]

Primers don't back out with high pressure, they flow outwards. When primers back out its usually a sign of a light load or long headspace. The ring is normal for Lapua brass.

 

[fourfive8]

Primers don't back out with high pressure, they flow outwards. When primers back out its usually a sign of a light load or long headspace. The ring is normal for Lapua brass.

That's it I believe. I see nothing much abnormal with those bases. Excess headspace can also cause flattened primers. Excess headspace will not cause high pressure nor higher than normal muzzle vel.

The sequence of events during firing in a rifle with excess headspace are: firing pin moves forward, primer fires, primer moves backward while forcing case forward, pressure rises in case as powder charge ignites, forward portion of case temporarily sticks to chamber walls while rear portion of case moves rearward stretching case just forward of web, head slams back against bolt face and re-seats primer (may show flattened primer because of re-seating process), pressure drops as bullet travels toward muzzle and exits. If there is excessive headspace--- a light, low pressure load will result in little case stretching rearward and the primer will remain in a backed-out position and will not be flattened.

The sequence of events for a case with minimal or near zero headspace are the same except the primer will not back out much and the case will not move forward much thus minimizing case stretch as the pressure rises. There won't be primer flattening caused by excess headspace because the primer re-seating will be minimal. If there is normal or minimal headspace then flattened primers will indicate high pressure.

 

[sestoppelman]

Here is a pic of a new Lapua case. Notice the"ring".

 

[perttime]

So, if the headspace was excessive, the cases stretched to fit. Getting them resized to spec might take some extra effort. Maybe needs trimming, too?

 

[sestoppelman]

Usually but OP says he had the HS fixed so no longer an issue.

 

[perttime]

The rifle is fixed, but the brass used before the fix might need something.

 

[sestoppelman]

Yeah, it might need sizing.

 

[BenKK]

Thank you, gents. Yes, the rifle has been fixed for some time. Will have a go at some case prep.

 

[bruce moulds]

ben,
firstly, the "ring " on the case around the primer pocket looks to be a manufacturing feature, and nothing to do with a problem.
there are 2 pressures to be aware of when reloading.
first is safety, and while those primers demonstrate high but safe pressures for those primers.
harder primers might suggest less pressures.
second is case life.
the test for this is what it feels like to seat new primers.
if they are loose going in, your cases have stretched, and you need to make a decision as to whether or not the stretch has gone past a safe level to seal gas pressure.
sometimes excess headspace can give the impression of excess pressure, as primers protrude on firing, and are then flattened as the case stretches back to meet the boltface.
this is where you will end up with case head separations after a number of reloads.
what I find interesting is the appearance of the primers in the first picture compared to the second picture.
there is a difference around the firing pin indentation, the second almost looking like there has been cratering which has flattened out.
this can also suggest excess headspace.
you can have correct headspace according to saami spec in relation to go and nogo gauges, but it is up to the reloader to then adjust ammunition to suit this.
the best way is to (critical) remove the firing pin from the bolt.
then chamber fired cases.
you need the rims to be under the extractor so that you can feel how the bolt closes.
ideally the bolt should close about 3/4 the way turned down freely, and then a little pressure should be felt.
do at least 3, and get a bit of an average feel.
if fired cases are a little firm all the way this is normal. however that is too tight on a reloaded case and the full length sizing die should be adjusted to achieve optimum feel.
if your loaded ammo has a loose bolt closure you could have excess headspace, but if it is 0.003" that, while being hard to measure, is still acceptable.
if bolt closure is a little hard, but doable, there is not excess headspace.
bruce.

 

[BenKK]

Thank you, Bruce.

I forgot to mention another aspect of this story: On factory ammunition, primers were definitely getting pushed-out, and one even popped-out completely. The gunsmith who did the installation of the new barrel attributed this to the ammunition rattling in the boxes over a couple of thousand kilometres of corrugations.

 

[bruce moulds]

ben,
is that before firing or during firing?
if before firing, I would suggest that there is something wrong with the ammunition to the extent that it should not be used!
no amount of rattling should cause primers in any ammunition, factory or reloaded, to do that.
either the primers are too small or the pockets are too big.
if the latter, throw the cases out.
you can establish this by seating primers with a hand tool (lee is good enough) and feel how tight they are.
if you now have excess headspace in your rifle, you will either need to correct it, or do this fix.
for excess headspace in a chamber, you can make the brass fit by fireforming the shoulder forward.
to do that safely you will need good neck tension, and seat your bullets 0.015" to 0.020" if you can into the lands to hold the case head back onto the boltface on firing.
this way the shoulder will blow forward, rather than the case stretching at the web causing an incipient head separation.
powder charges will need to be established for this job.
just to muddy the waters, you have 2 gunsmiths that have different definitions of correct headspace.
which if either is right.
you have some homework to do.
bruce.

 

[BenKK]

That was during firing (primers popping out).

It was difficult to lift the bolt, and eventually I had to use a hammer to open it. I took it to a gunsmith and he fixed it.

The rifle now shoots appropriate speeds and lifting the bolt is easy. No more primers popping out.

Yes, the “corrugation fault” was “interesting”.

 

[WAB]

Thank you, Bruce.

I forgot to mention another aspect of this story: On factory ammunition, primers were definitely getting pushed-out, and one even popped-out completely. The gunsmith who did the installation of the new barrel attributed this to the ammunition rattling in the boxes over a couple of thousand kilometres of corrugations.

That seems like a stretch to me. If you have primers coming completely out of the case there is a problem somewhere and I seriously doubt that it has to do with driving down a rough road with the ammo.

 

[bruce moulds]

I just checked some 6.5/284 lapua brass and it has a similar marl around the primer pocket to ben's.
almost looks like military crimp without the crimp.
bruce.

 

[bruce moulds]

the word gunsmith does not necessarily imply god like qualities.
there are good ones, and they are the ones you need to know.
bruce.