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what other than the wrong powder causes these signs?

Discussion in 'Handloading and Reloading' started by Detritus, Jan 29, 2010.

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  1. Detritus

    Detritus Member

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    gentlemen, for the first time since I first started handloading at age 14 (near 20 years off and on) I have offically scared myself.

    last week loaded up a small batch of .308, using Prvi Partizan (same as wolf Gold) brass, Winchester WLR primers, 175gr SMKs, and 41grs of IMR 4895 (the "Starting load" from the hodgdon on-line data).

    I only fired three rounds, and quit because I got the following results...

    Bolt was VERY stiff to open on the first two (should have stopped here and investigated further) case heads both looked like Left hand case in pic below, on #3 bolt was hard to lift, would not open (extract) had to use cleaning rod down boreto tap bolt open/ the case out, case is on Right in picture. yes that is a blown out primer, which is blackened around over 3/4 of it's circumfrence (firing pin mark indentical to Left hand example, but the primer it's edges are blwon out square to the pocket). since i pushed out the case with the gun vertical, primer was resting on the breech face

    007.jpg

    since this was with a starting load, a full 4 grains below the listed max, i'm flumoxed as to how i got pressure signs like this.
    Also, I have used this load previously, in this gun and in the same brand (but possibly different Lot) of brass with no such signs.

    help me understand, where or If i screwed this up. what all CAN cause this.

    If more info is needed please ask and i will provide to the best of my ability

    thank you for your time and any info you can give.
     
  2. bullseye308

    bullseye308 Member

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    First thing I would do is pull a couple rounds and double check the powder charge.
     
  3. Kernel

    Kernel Member

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    Is it possible this brass was shot in another rifle prior to being used in your bolt gun?
     
  4. Cosmoline

    Cosmoline Member

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    Just to double check, you were loading with IMR 4895 not H-4895, right?

    I would make sure your scale is giving you accurate readings.
     
  5. highorder

    highorder Member

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    Seconded. I think you have a problem with the scale?
     
  6. Detritus

    Detritus Member

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    tommorrow i'm planning on pulling the remaining 32 rds of this load, reweighing a few with not only the scale i used this time, but both of my other powder scales (another Lee perfect powder scale, and an old Herters) to cross check.

    and Yes it was IMR 4895
    IMG_0202.jpg
    the only three powders that I've even brought home since moving into this house/workroom, are IMR4895, an unopened pound of IMR 4007 SSC, and the pound of W231 that hasn't left the cabinet in over a year (had to open cabinet to find it and check what it was).

    No, I bought all of the PPU (Prvi Partizan) ammo as factory fresh ammo from midway, fired it in this rifle and this rifle only. now 50 out of the 140 pieces of PPU that i have, could possibly be on their second reloading (third firing ever). but none of the PPU brass has been fired through any other rifle.
     
  7. R.W.Dale

    R.W.Dale Member

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    Have you fired this rifle before? What kind of firearm are we dealing with here.


    What I'm driving at is sometimes the gun is as much to blame as the load. Also were the rounds in question chronographed?
     
  8. Tim the student

    Tim the student Member

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    I am a new reloader, but with as close as the burn rates are, would that be a feasible possibility? Not trying to sharpshoot, trying to learn myself here.

    Is that brass military, and significantly thicker than civilian? That's what I would think (me and my inexperienced self that is) assuming the scale is good.
     
  9. Detritus

    Detritus Member

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    Rem. 700 SPS-Varmint

    No the rounds were not chrono'ed as i do not at this time Own a chronograph.


    weird thought hit me, there may have been a small amount of oil in the chamber...
    this rifle had been in storage since june of last year, and since i live in coastal texas and this area could make WOOD rust, I oiled it down well inside and out before storage. I know i patched the bore to remove any oil, but I didn't go back with any thing to check/swab the chamber to make sure.

    just in case that could contribute.
     
  10. Detritus

    Detritus Member

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    they're close, but you still do NOT wanna mix up the load data.


    as for the brass, I have no idea if it's any thicker, probably is since Prvi Partizan is as i understand it pretty much the Serbian "State ammo factory" but still a starting load shouldn't be doing this even with thicker brass, the starting loads are supposed to be low enough to safely begin with regardless of brass (as long as the brass is within reasonable specs)

    If it turns out that the charges really are 41grs, then i'll retry this load in the small batch of Lake City brass I have on hand.
     
  11. Tim the student

    Tim the student Member

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    I fully agree, but I wouldn't think it would be possible to do that with these two powders even if they were switched up.

    ETA:
    I wouldn't think the brass alone would do that by any means, but if the scale was miscalibrated by a grain or two, and this brass is significantly thicker than commercial, then I would think that combination could do it.

    ETA again: Did you weigh the bullets? The factory may have mislabeled a box.
     
    Last edited: Jan 29, 2010
  12. Detritus

    Detritus Member

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    No, but when i made my first batch of hand loads for this rifle, i used 50 bullets from this same box of 100 and experienced none of these signs. and i expect if they were the cause, i beleive would have seen signs of something.
     
  13. Tim the student

    Tim the student Member

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    Just a thought; I was trying to think of things that may have contributed to it, other than the scale issue.
     
  14. Oyeboten

    Oyeboten Member

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    Are you sure these are Rifle Primers ( and not Pistol Primers)?
     
  15. nicholst55

    nicholst55 Member

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    Does the brass need to be trimmed? Were the bullets seated into the lands? Both of those conditions will increase pressures, as you're probably aware.
     
  16. Detritus

    Detritus Member

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    Yep, have 3K of them sitting here on the self, and this is the tray the primers in this batch came from (i keep any component boxes/containers till after i test fire ammo created with those components)

    IMG_0205.jpg

    all brass used measured 2.010-2.013" after sizing. According to the cartridge diagram that came with my dies, trim length for .308 is 2.015" . is that correct?

    the OAL was 2.800" and i'm pretty sure that the throat on most remington factory barrels is long enough that the bullet was not in the lands.
     
    Last edited: Jan 29, 2010
  17. Claymore1500

    Claymore1500 Member

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    Just a thought, (I only load for revolver, no rifle press yet) check bullet seating depth, crimp, and possibly, check for a carbon ring in the chamber, could be simulating an over crimp condition when firing.

    Just a thought.
     
  18. qajaq59

    qajaq59 Member

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    If it's not the powder this would be my guess too.
     
  19. longdayjake

    longdayjake Member

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    I am surprised no one has mentioned this one yet. Is it possible that you had your bullets seated too long and they were engaging the rifling before you fired? I have seen that really increase pressures in many guns.
     
  20. 243winxb

    243winxb Member

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    308 Winchester Maximum Loaded Neck Diameter .3433"

    Neck diameter of a loaded round should not be larger than .343" :uhoh: If it is, bullet is crimped in the chamber, pressure goes up. :cuss: Check measurement of a loaded round to the maximums listed here. http://www.stevespages.com/page8d.htm :) Check a fired cases neck diameter, has it expanded .002" or more over the loaded rounds diameter? :scrutiny:
     
  21. 243winxb

    243winxb Member

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    To Much Powder?

    Trim length is 2.005" :scrutiny: Maximum is 2.015" You are OK there.
    The powder scale may have been set incorrectly for your small batch. One notch is 5GR, that would do it if you loaded 46.0gr by mistake. We will know after you pull bullets. :confused:
     
    Last edited: Jan 29, 2010
  22. Bwana John

    Bwana John Member

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    Weigh the brass. If it is significantly heaver than commercial it could be your problem. Thicker mil-spec brass requires 10% reduction for starting loads.
     
  23. Mr_Pale_Horse

    Mr_Pale_Horse Member

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    1. Measure and report the case capacity for the PPU cases. Fill with water and weigh the water in grains.

    2. If you can, make sure the loaded cases were not resized short, resulting in excess headspace. Partial full length resize or neck size.

    3. IMR 4895 can detonate at about 10% below minimum load density. Given an unknown case capacity, the load may be too light.
     
  24. essayons21

    essayons21 Member

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    My guess would be a scale that was not zeroed, or on an angle.

    Other option would be something in the chamber/throat area, i.e. oil.

    I don't think you have an issue with the brass, I shoot prvi partisan all the time in a remington, and the increase in pressure/velocity wouldn't be causing those signs if you started at min. load.

    The first thing I thought was bullets seated into the lands. Double check the zero on your calipers. I have heard, but never seen, that too little neck tension with a bullet seated well off the lands can cause the same phenomenon, basically the primer ignition will push the bullet into the lands, causing pressure spikes when the powder ignites. Maybe check the neck tension.

    If all that fails, contact IMR with the batch number of the powder.
     
  25. NVMM

    NVMM Member

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    I think oil in the chamber has pushed the cartridge back against the bolt leaving the impression.
    I think your fireing pin hole is on the large side allowing for primer flow.
    I don't think you are seeing high pressure signs as your primer looks rather normal.
    The primer has not filled out to the edges of the primer pocket.
    I would be interested in your findings.
    Thanks
     
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