What blew up my gun?

Discussion in 'Long Range Hunting & Shooting' started by normyt, Sep 9, 2019.


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  1. Barrelnut

    Barrelnut Well-Known Member

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    Duke, you should research this a bit. An underload is way more likely to cause this than an overload. It is a good thing to understand.
     
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  2. yorke-1

    yorke-1 Well-Known Member

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    So the charge was up to or possibly a little over 37.0gr of Varget with a 55gr bullet? That's not enough to cause what's seen here. Hodgdon lists 36.5gr of Varget for a 55gr Speer SP. So a 55gr V-Max will be a little longer, I get that. For anyone with Quickload, run the numbers on a 55gr V-max and an over load of Varget and see what you get. I looked at predicted pressures for up to 39.0gr of Varget and came in under (barely) 80K psi.

    I've never seen a Savage bolt head fail like that, and I've seen (and done) some VERY stupid things to Savage actions over the years. And what about the front baffle behind the bolt head, where's that? The action failed right where the bolt head failed.

    I just don't think this is the result of a 75K psi load.
     
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  3. antelopedundee

    antelopedundee Well-Known Member

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    I'd use the beamer then. I have a little cheapie battery powered unit too that's right on the gnat's *Rule 4 Violation* and not subject to fluctuations from humidity or air currents. It's not quire as sensitive as the beam unit which is an old Bonanza unit that's about 45 years old.
     
  4. sw282

    sw282 Well-Known Member

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    normt-- l don't believe your load practices caused the kaboom. Nosler manuel says 35gr of Varget fills 88% of the case volume. Nosler says 36gr of Varget is MAX with a 55gr bullet. You were 1 grain under max with Nosler. Hornady says 34.7gr is Max for a 55gr VMAX. You were only 3/10 of a grain over using Hornady cases.. Hornady cases usually have the smallest case volume. Remington are usually the roomiest around... LYMAN manuel#50 says 37gr is max load for Varget using a 55gr VMAX bullet.. @35 you are 2 gr under max... Speer #14 says 35gr of Varget is starting load for a 55gr bullet using a Remington case.. Max is 37gr... Also max case length is 1.912''...None of your cases exceeded 1.912''... l don't know what blew up your gun... But l can say I'm pretty sure from the facts you presented here... IT WAS ''NOT'' YOUR AMMO.
     
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  5. sw282

    sw282 Well-Known Member

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    Another couple points l would like to make... l think it would be impossible for it to be pistol powder since Norm said in a couple of posts he doesn't load for pistols, nor does he have any pistol powder...
    With regards to scales-- l have 5 powder scales... 2 digital- 3 are mechanical or beam scales.. l always use at least one of each and sometimes two. l ALWAYS weigh powder charges.. one at a time.. l have to be careful with my reloading because l shoot competition lHMSA silhouettes. Lots of people close by, often children...
    VARGET is a very wise choice for reloading with... lts not really slow burning like some of the powders used in compressed loads. @88% case capacity, there's room for VARGET to expand during a hot day on the prairie
     
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  6. woodsmanlw

    woodsmanlw Member

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    "All cases had 34.6gn of Varget except 5had 35gn, 3 had 36gn & 1 had 37gn
    I went back to Hornady Load Book and 34.6gn is absolute Max for 55Gn V-Max bullet
    The loads I've been making are for 50Gn V-Max bullet. (which I used previously)
    Max amount of Varget I could get in a 22-250 case is 39gn
    Looks like I've been living on the edge for quite a while."

    Not so fast..:) Now obviously we all want to be safe and must be very careful when reloading etc, so consider all the safety issues as, well considered. Now, let's look at real world 22-250 reloading, using 55gr bullets and Varget. The Hornady handbook is notoriously conservative, I can go into it if you want but let's just note that for now. The Hodgedon reloading center lists 36.5 for a spr sp as max. Other handbooks vary, so the takeaway is that max is not consistent for a variety of reasons. The most realistic thing we have to remember is every shot is a combination of ammunition with all of its variables and the firearm it is fired from, with all of its variables with the environment that it is fired in with all of its variables. You can look around shooting forums and find people that load this load up to the Hodgedon level and higher all over the place. Are they wrong? Could be. But it's only wrong if it's wrong for the particular set of variables in play for a particular situation. The max loads are meant to provide a safe margin for handloaders and if people work up their loads correctly, watching for pressure signs then going up to the max (and dare I say beyond, with the rather obvious caveats) is fine.
    We can glean several points from all this. First and foremost, we cannot take anything for granted and even assume a maximum load printed in a book is "safe" for a particular set of variables and conversely that maximum may not be a maximum for some other set of variables. One person may be shooting at 30 degrees F, temperature insensitive powder, have a beefy rifle with a long throat, brass with higher volume etc, all making for being able to shoot a load higher than "max". Another person will see definite pressure at well below max because he is out in the summer sun shooting bputs all day long and his rifle/ammo combo is more prone to pressure.
    Secondly, we cannot assume anything about the variables involved in our shooting. We strive to have consistent ammo, but as you show here, you have a pretty wide spread in powder weights that would make me swear off powder throws forever (assuming you are using a throw). But even if we do have perfectly consistent loads, what about our shooting conditions? What about fouling, what about... well you get the idea. We also cannot ignore the combined affect of our variables and sometimes we have to be careful to not overestimate the affect of some variables. There is a fairly reliable story that an early and prolific adapter of the 22-250 was known to take a case and dip in a container of W760, I think, brush off the powder from the top of the case and seat a bullet. It would not only be fine but even fairly accurate. The 22-250 is one of the most forgiving cartridges to load one can find, not that I would recommend doing what this guy did.
    Lastly, due to those variables that same ammo that you work up for your rifle and works fine, could be overpressure in someone else's rifle, or at a minimum, could have totally worthless accuracy. Or, holding the ammo and rifle as constants, you could find your rifle shoots great early in the morning while cool and loses accuracy as it heats up or maybe even shows pressure as it heats up. Who knows.
    As for pressures developed with Varget etc, and did it blow your rifle up as a matter of over pressure, I'm not so sure of that. The pressure it took to do that to your rifle probably cannot be achieved with the amount of Varget you can fit in the cartridge. This is certainly speculation but that is a lot of damage and most guns are proofed in the factory with loads that are likely in the range of what a full cartridge of Varget would be so I'm skeptical that this was the issue. Proof testing in most cases specifies 25% over max pressure so that puts the rifle as being tested at over 80,000 psi, which I'm not sure 39gr Varget will achieve and if it can, how much more can it achieve since the rifle has already be proofed over 80,000. I could be wrong but that's how it looks. Glad you were not hurt.
     
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  7. Swamplord

    Swamplord Well-Known Member

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    Well it's a Savage so there's that
     
  8. woodsmanlw

    woodsmanlw Member

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    I like both. I use the digital scale from the RCBS powder measure to dispense the powder then I drop either every 3rd or every one on the beam scale to verify. The electronic measure speeds things up and I find that I can go a long time before the scale drifts. But, you must make sure both the beam and electronic scale are level and calibrated. I also have an antistatic cord attached to the electronic scale to bleed off static charge. This is helpful for both the powder sticking and accuracy.
     
  9. rbTanzan

    rbTanzan Well-Known Member

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    It looks to me like you put a 243 round in your 22-250.
    Do you own any other -08-cased rounds? 243, 260, etc?
    It looks like the pressure and blow up happened at the chamber.
    I've seen this before.
     
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  10. yorke-1

    yorke-1 Well-Known Member

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    There’s no way you could beat the bolt closed on a 243 Win round in a 22-250 chamber.
     
  11. rbTanzan

    rbTanzan Well-Known Member

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    Here is a Tikka:
    note same position of scope, but top of receiver broke loose and bolt broke into three pieces plus the bolt handle. A 308 was placed in a 270. No one hurt seriously.
    [​IMG]
     
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  12. rbTanzan

    rbTanzan Well-Known Member

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    Yes, you are correct. It would take a much shorter round. So a squibb load or wrong powder become the options as mentioned.
     
  13. normyt

    normyt Active Member

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    No 243 or 08's, closest caliber I have is 270
     
  14. MNbogboy

    MNbogboy Well-Known Member

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    We all have to keep in mind that the "strength" of the rifle does not come to play here. Rather the brass case could not take the pressure of the round in question.
    Whether it was overcharge, undercharge, blocked or other barrel conditions, the pressure generated overcame the "strength" built into the case head. All damage occurred at and from the point of rupture. If no rupture then no visible damage.
    Over pressure is the culprit no matter what caused it. Could have been the brass itself.