Diagnose my ammo problem...

[spleify]

Im guessing loose primer pockets also.

[Hoser]

I have only seen that once before. A new reloader pushed the shoulders back too far essentially creating excessive headspace. That combined with too light of a load it looked just like that.

But... Southwest Ammo is a solid company that knows what they are doing. I would call them and ask.

[Hoser]

If the primers can be pushed back in with your finger or are simply falling out, the ammo was too spicey and the primer pockets are shot.

Measure an unfired case at the web and then measure a fired case.

[spqrzilla]

Hoser's advice - candy ass that it is - is dead on.

Its fascinating how very different conditions can create what are superficially similar symptoms.

[Zombie Steve]

I'll agree there has to be a lot of room for the primer to come out like that... headspace is probably part of the problem.

I had this same problem with .308 when I started reloading. Pushed the shoulder too much, and the primers would back out (well, they all back out, but when the powder goes off it gets re-seated by the bolt face as the brass expands). This only happened on my start and low end charges. As I worked up, the issue went away.

Now that I'm seeing your pic on my computer and not on my phone, I don't see any issue with smearing / swiping or extractor marks on the brass. I'm still guessing too low of pressure.

Do you have a micrometer? Mic the case web before and after. More than .0005" growth in the case web on new brass is a pretty good indicator of high pressure.

If the issue was loose primer pockets, they'd be flattened.

[Fentonite]

Ok, so here is how ignorant I am... I don't know where the "web" is on a case. Call me what you will. But what the hell, I decided to measure some rounds. I measured the OD of the groove that the extractor goes in...

On an unfired round, the measurement was consistenly 0.398-0.400:


On fired brass that didn't have the problem, the measurement remained 0.398-0.400:


On the four rounds that had primer problems, the measurements were 0.405, 0.408, 0.410 and 0.411:


Seems like this would mean something, to someone smarter than me...

[JM Ver. 2.0]

Look up case specs for the primer pocket. Measure that. But I'd agree the fired cases with primer issues are out of spec.

Sent from my teepee using smoke signals.

[Zombie Steve]

Web measurement would be the base of the case just north of the extractor groove.

[spqrzilla]

Its hard to measure accurately in the extractor groove with calipers but if you have got good measurements, then a batch of excessively soft brass is a possibility.

[Fentonite]

Seems odd - there's no significant difference among web measurements between unfired, fired, and the problematic 4 fired rounds. Just the difference within the extractor groove. Thanks for everybody's input. I'll post whatever response Southwest Ammunition gives me.