Checking for Incipient Case Head Separation?

Discussion in 'The Ammo & Reloading Forum' started by Josh Smith, Dec 6, 2011.

  1. Josh Smith

    Josh Smith Member

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    Hello,

    I use a straightened safety pin with a 90 degree bend on the end to check for incipient case head separation.

    My concern is that I've never felt a ring.

    My oldest rifle brass is 7.62x54R Winchester. The majority of it has been reloaded three to five times apiece using mild to warm loads, depending on whose data you use.

    I've been loading at 47 grains of Varget under 150grn bullets these days. The previous load was 47.2 grains of Varget or H335. (I only used one pound of H335; didn't like the stuff).

    I'm dropping back to 45 grains Varget because I just don't need the velocity at the ranges I shoot at. Heck, I only went up to 47 grains in the first place because it's Hodgdon's minimum. After looking over more data and deciding I won't flash the powder I'm going back to it.

    The first two times I reloaded I sized full length, then something like 3/4 length. I only neck size now because I figure the military chambers are a bit generous, and I like headspacing on the shoulder.

    Point being, these cases have sizing marks in different spots and I just really don't trust using the outside to judge. There are no new bright rings, and the rings that I see from sizing have obviously been there for a bit. None are raised.

    So... I guess my concern is that these cases have more than a few reloadings on them and I think I should be feeling something I'm not feeling.

    Advice?

    Thanks,

    Josh
  2. woolleyworm

    woolleyworm Active Member

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    If you're not feeling it, then it's not there IMO. Your loads are mild and I think you've got several more loads to safely use that brass. My best advice is this; if you have a die grinder and a small cut-off wheel, split a couple of cases and give it a full inspection. You'll ruin a case or two, but have all the info you're looking for and some peace of mind too. If you don't have means to split the case; send'em to me and I'll do some dissection on them and post pics and measurements.
  3. Bindernut

    Bindernut Well-Known Member

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    With mild loads and you only partially full-length resizing, I wouldn't suspect that you will have any problems with case head separation.
    Tapered cartridges like the 7.62x54R and the 30-30Win are less prone to it as well since they will slip back out of the chamber under pressure easier than a straighter-walled case will. About the only way you'd have problems is if your Mosin has excessive headspace and/or you're full-length resizing the brass so that there is too much free space between the chamber and the case.

    You're checking the right way. And yes once you have felt one it's easy to tell if your probe is snagging on that little stretch mark. It's that first one that is the hardest to ID. Woolley's idea of halving a case to check isn't a bad idea...and you can use that one to see about how your probe is working when you're poking around for that weak spot.
    I'm guessing you've seen the pictures of case head separations either in manuals or online.

    How it happens...
    The case will get mashed all the way into the front of the chamber when the firing pin first contacts the primer. If there's too much room in the chamber, there will be a gap from the bolt face to the cartridge head (case head gap).
    After it's all the way up front, the pin will detonate the primer. That will light the powder, which will expand the case walls so the grip the chamber. With the case gripping the walls, if there is any excess case head gap, the case will stretch backwards until it seats against the bolt face. Since most of the case has expanded to grip the chamber, that stretching occurs near the head of the case.
  4. myfriendis410

    myfriendis410 Member

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    I made a tool to check for the same problem but might suggest you do what I did. I ground the face of it so that it comes to a point so that you can feel the groove more easily. A stiffer piece of wire might also be a good idea so that it transmits that feel more readily to your hand. A coathanger might serve.
  5. Bindernut

    Bindernut Well-Known Member

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    A big safety pin with a bend in the end is what I use too. It's nice good springy steel, is already pointed on the end, and the head on it makes for a decent handle.
  6. 1 Eyed Jack

    1 Eyed Jack New Member

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    What are you trying to find with the safety pin? the beginning of a crack on the inside of the case?
  7. woolleyworm

    woolleyworm Active Member

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    Yes; if there is impending failure for a case head seperation; 99% of the time, you'll be able to feel it BEFORE it becomes an issue. A bright ring that is visible on the outside is an indicator also, but usually you'll be able to "drag" it internally and feel it first.
  8. 1 Eyed Jack

    1 Eyed Jack New Member

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    Gotcha, thanks, I am reloading old brass that has been reloaded 3-4 times, I noticed what looks like a noticable ring on much of the brass, maybe 1/3-1/2 inch up the case and wondered about it, I had an experienced reloader look at them and he said they were in fine shape, but I will check them with the safety pin and see what I find, I think they are OK and the ring/mark is just where the sizing die stops, but want to be sure,
  9. woolleyworm

    woolleyworm Active Member

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    Is this "ring" occuring after the first resizing? Definetely check it out.
  10. 1 Eyed Jack

    1 Eyed Jack New Member

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    I don't recall, I resized very early on during my research and prep to reload for the first time, there are no other signs of overpressure or general case wear at all, and when I trimmed the cases it was the first time they had ever been trimmed and very little, if any trimming actually was needed, I still believe there is very little wear on these cases, but I will check this on the few reloads/cases that I have fired with this new to me technique, can't be too careful,
  11. 1 Eyed Jack

    1 Eyed Jack New Member

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    I tried to snap some pics, but don't know if you can see it or not, seemed to be on 15% or so of the 100 cases I reloaded, and seems to show up more on the fired cases, it does look like it is where the sizing die stops, I'll check back on this later and try the safety pin thing, got get ready and take my wife to the hospital for surgery, I'll report back in a couple days after the pin check, but right now it looks like nothing to worry about, but I will check it,

    thanks,

    Attached Files:

  12. accident

    accident Well-Known Member Supporting Member

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    I hate to steer away the direction of the conversation but was wondering how common is it to come across a gun with a larger than normal space between the bolt face and the cart. head? I's case head separation the only indication?
  13. JLA

    JLA Well-Known Member

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    That excessive headspace accident. and casehead separation is one of the results of excessive headspace.

    Most bottleneck rifle cartridges will exhibit a bright ring above the web of the case after resizing, this is a clue that the case will separate on the next firing.

    Anyone whos ever reloaded for a .303 british enfield rifle becomes a pro at spotting incipient casehead separation.
  14. accident

    accident Well-Known Member Supporting Member

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    JLA,I've been reloading 4 rifle calibers for 2 years now,about the time I think I know a little I turn around and ask a stupid question like that.I should have reread the headspace sticky then I would have realized the answer before I showed such ignorance with my question.Sorry. Joe
  15. whymememe

    whymememe Former Guest

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    Guys, I'm new at this, but I'm tech minded. If the case blows out. Would it just damage the chamber. What could be the possible outcome?
  16. woolleyworm

    woolleyworm Active Member

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    Worst case scenario is a major KB. Think about this; you've got a cartridge rated at 55,000 psi and the case head seperates; guess how much pressure you've just released into your chamber and very close to your face. There is never any way to tell exactly what will happen; granted, most times the action will hold up, but sometimes not.
  17. JLA

    JLA Well-Known Member

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    99% of the time the action will safely contain a casehead separation. most modern boltactions have vents either in the bolt or on the forward reciever ring to vent gas away from the shooter. But you will still likely get a face full of hot gas and maybe some singed eyebrows.

    Usually mechanical failure thats load related is resulted from a gross overcharged case or a barrel obstruction, and in some cases could be from shooting the wrong ammo in the weapon. Those are the cases that cause those horrendous burst barrel stories or the bolt blowing out of the reciever and killing the shooter.
    Last edited: Dec 7, 2011
  18. reynolds357

    reynolds357 Former Guest

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    The only separations I have ever had have been on belted magnums being pushed way past where they were designed to go. I was doing load development for wildcats and a tiny bit of powder caused a huge difference in pressure. Wicked things happen when you are shooting stuff that is WAAAAAAAYYYYY overbore. I separated a .264 Win mag one time, but I blame that one on factory defective brass. A guy I shoot with has them all the time. He duplexes powder. I am not even brave enough to try to learn that stupid art.
    Last edited: Dec 7, 2011
  19. myfriendis410

    myfriendis410 Member

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    Case head failure is more common in belted magnums and is a really good reason to examine your brass. Most of the problem with the belted magnums is because you are not able to fl size all the way to the belt. Recently I started using a tool designed to eliminate that problem and hope to see better case life with my magnums. That said; I've reloaded some of my .300 win mag brass at least 8 times with absolutely NO signs of failure. It's all Nosler brass, and the pressures are within spec, but I do better with that rifle than I do with my two 7 mm rem mags. I have a Ruger No. 1 that I fear has some issues with headspace based on the number of failures.

    I had a case fail in that rifle several years ago. I was crosshairing a big hog at the time and the round did it's job, but my rifle was immediately rendered useless until I could get the case out of the chamber. a .30 caliber brush carefully inserted into the breech withdrew the brass without any problem.

    In the case of the belted magnums; the belt is there to contain pressure in the event of a failure. It's an artifact of the times. Brass was not as well made back then as it is now. Most rifles are designed to vent gases away from the shooter in the event of a case failure.
  20. whymememe

    whymememe Former Guest

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    When my unit at Benning was doing some 16 requalification, One of my friends had a 16 blow up in his face. He was O.K. but that 16 was obliterated. Here's my theory of what happened.

    I had noticed some of the boys taking the rounds apart and pouring out the powder. I thought they were just taking a souviner. I think one of these rounds got put in the magazine by accident. I think the primer pushed the ball part way into the barrel and when the next round went off the pressure blew up the side of the 16.

    Is this feasible?
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