Early case head separation?

[Bixster_inc]

Spitballing here but it’s hard to think of a sell by date for ammo when my friend, who is out to collect every gun from WW2 from every country involved that can legally be bought regularly buys and uses without issue 50+ year old surplus ammo. Well he did buy a box of 6.5 Jap that was straight duds but 50 rounds out of the thousands he’s hunted down isn’t bad.

On a side note:
I’m switching brands on virgin brass. The Hornady stuff I picked up today is “ready to load” out of the box. Every case I checked fits nicely in the case gauge and are all at 2.005” on the nose. Totally worth the extra .10/case over the Winchester and was the same price per 50 as the Starline but both of those require some prep first.

If I get 5 firings out of it we’re talking roughly .68/round on ammo that’d likely slap on $1.50/rd factory stuff. I’ll however probably continue to use Starline for my .44 mag/special and 45-70 loads.

 

[243winxb]

Factory ammo/new brass can be damaged on the 1st firing in a rifle with excessive headspace.

the headspacing on most 7.62 NATO chambers will run 0.006 to 0.010 inch longer than their sporting rifle

https://www.shootingillustrated.com/articles/2018/8/19/308-win-vs-762-nato-whats-the-difference/

 

[Nature Boy]

I have had a bad lot of Lake City (LC 04) that completely fractured through the case head and blew the mag out on my M1a.

Was that brass purchased as once fired or was it new?

I never had any case head separation with my M1A but I also avoided any once fired LC brass as it would have almost assuredly been fired through an M240.

I had new LC brass on it’s 14th firing through my M1A. Cut one open and there was only a slight thinning at the case head. Could have gone several more cycles

 

[fguffey]

Two takeaways on the brass was I was surprised to find fine lines on the cases after just one firing. I tossed those and moved on with the rest. Another surprise was the length of the spent casings. Usually I cut my .308’s down to 2.000” but many were much shorter. I decided to take them down to 1.990” to get some semblance of uniformity but still many were under that.

No mystery, the case shortens when fired; this happens when the case forms to the chamber. When the case expands to form to the chamber the neck is pulled back.

If the firing pin drives the case forward when it strikes the primer the shoulder of the case is against the shoulder of the chamber when fired. That is different, if the shoulder of the case is against the shoulder of the chamber when fired the case locks onto the chamber, if the case is locked to the chamber and the case head is not against the bolt face the only place for the case to stretch is between the case head and case body.

F. Guffey

 

[Charlie98]

Was that brass purchased as once fired or was it new?

No, it was once fired, processed... and, yes, certainly 90% machine-gun fired.

 

[fguffey]

Factory ammo/new brass can be damaged on the 1st firing in a rifle with excessive headspace.

I choose to size or form cases to off set the length of the chamber. Again, I have one chamber that is .002" longer than a field reject length chamber meaning when I fire minimum length/full length/factor over the counter ammo in that chamber I have .016" clearance. When I fire minimum length/full length sized ammo in that chamber the case shortens from the end of the neck to the case head and gets longer from the shoulder/case body juncture to the case head.

F. Guffey

 

[Nature Boy]

No, it was once fired, processed... and, yes, certainly 90% machine-gun fired.

That’s the issue I’m guessing

 

[fguffey]

That’s the issue I’m guessing

Is there a reloader that can determine if a case has been returned to minimum length after sizing? Has anyone thought of determining if the case has been sized before lowering the ram after sizing?

F. Guffey

 

[Blue68f100]

If it's truly once fired, when you size it, it's length is going to me significantly longer if fired in a MG. I helped a neighbor with LC 7.62 that he bought online, some would be very difficult to size. I annealed all the brass which make it easier to size. Then after sizing started measuring the lengths. All the MG brass was 0.015"-0.020"+ longer than all the brass. Did not think to measure before hand. You may see a difference but the spread is more than likely less. All depends on what size the chamber is, over gassed, MG , and what gun it was fired in. If a bolt gun very little normally. AR's slighly more, MG a lot.

 

[Nature Boy]

OK, I’ll bite

Is there a reloader that can determine if a case has been returned to minimum length after sizing?

What is this minimum length that are you referring to? Sizing affects multiple case dimensions, both linear and non linear. There are tools that help the “reloader” determine that both have been affected to the desired degree. Some are attribute gages, some are empirical measuring tools.

So the vagaries of your question not withstanding, the answer is yes, a reloader can determine and not just one, but countless reloaders can and do, every day, and have been doing so since before you were just a glint in your daddy’s eye

Has anyone thought of determining if the case has been sized before lowering the ram after sizing?

This sounds more like some quantum mechanics thought experiment than a question for a reloading forum. Sort of a “Schrodingers cat” paradox-thing”

My answer is that the case has been sized, hasn’t been sized and all infinite possible permutations of partially size until the “reloader” measures it and fixes its state.

https://en.m.wikipedia.org/wiki/Schrödinger's_cat

 

[Nature Boy]

If it's truly once fired, when you size it, it's length is going to me significantly longer if fired in a MG. I helped a neighbor with LC 7.62 that he bought online, some would be very difficult to size. I annealed all the brass which make it easier to size. Then after sizing started measuring the lengths. All the MG brass was 0.015"-0.020"+ longer than all the brass. Did not think to measure before hand. You may see a difference but the spread is more than likely less. All depends on what size the chamber is, over gassed, MG , and what gun it was fired in. If a bolt gun very little normally. AR's slighly more, MG a lot.

I bought some once fired MG brass and had the same experience when re sizing it. Never shot any of it after. It’s sitting in a plastic tote waiting for a disposition

 

[Swampman]

Yep, some brass is just crap.

These Winchester .223 cases were all out of @1000 I picked up at a police shoot a few years back. All were from once fired 63 grain Power Point loads.

I picked up almost half again as many Remington .223 cases that day and not one showed a split neck/shoulder, so I doubt it was a particular weapon causing the problem.

As a general rule, I've always far preferred Winchester brass to Remington, but anyone can have a bad production run.

 

[Demi-human]

I tried the paper clip trick but couldn’t feel anything on the inside. Outside however as you can see has a noticeable ring/indentation. The second pic is what I would consider to be a good one.

It looks to me that the first case suffered from overly energetic chambering, that may be why you felt no ridge. It seems the mark is a bit high for a head separation, though I imagine they can become fatigued at any place.

It is always fun to see how many cycles we can get out of a set of cases, but in the end they are relatively inexpensive and endlessly recyclable.

Make those old cases into new ones, scrap them.