Results 1 to 8 of 8

Thread: Primers backing out. ???

  1. #1
    Member highestview's Avatar
    Join Date
    Nov 2007
    Location
    Haines
    Posts
    1,308

    Default Primers backing out. ???

    Had the primers on my 308 Winchester backing out a tiny little bit (less than 1/2 a mm or so) out there on Saturday. Never had that happen. Any ideas on why they would be doing that? Some of the preliminary stuff I read said possibly low pressure but I'm not sure.

    The Load Specs:
    PPV 308 Winchester brass, once fired from their 168gr match ammo.
    Powder: Reloader 15 43.5 grains
    Primer: WLR magnum
    Bullet: Hornady 150gr spbt and Sierra 150gr spbt, both batches backed out a little.
    Rifle: Ruger Scout Rifle

    The Sierra manual listed the max load for RL-15 and these bullets at 44.8 grains. I figured 43.5 would be a reasonable place to start. I thought that considering the short barrel and cold temperatures a magnum primer might help get all the potential out of a lower velocity round. I didn't feel any higher recoil or sticky bolt lift. The cases themselves dont show any signs of high pressure. I dont really know what to think here. I've never had that happen on any of my other loads. As far as brass/headspacing issues, I shot all that PPV match ammo through my Scout rifle and it chambered fine, shot excellent so I cant imagine it being an issue. Any ideas guys? Could that brand of brass just have bad primer pockets? Any safety issues presented by primers doing this?
    Born in Alaska: The boundary lines have fallen for me in pleasant places; surely I have a delightful inheritance. Psalm 16:6

  2. #2
    Member marshall's Avatar
    Join Date
    Nov 2007
    Location
    Near Phoenix, AZ
    Posts
    1,814

    Default

    Primers coming out is generally a loose primer pocket, over pressure, to much head space. If the case grew when fired and grabbed the chamber wall and didn't come back and hit the bolt face the primer would come out as much as the head space clearance allows.

    Do you see any head swelling?

    Are there any burnt, dark areas around the primer indicating a leak?

    Did the primer mushroom a bit when it came back and hit the bolt face?

    Is it cratered?

    I'm not buying the WLR Magnum excuse. An Independence lab test I read documented the WLRM having a 2000psi higher pressure than typical LR primers. Such a small charge of extruded powder doesn't require magnum primers at any temperature.

  3. #3
    Member highestview's Avatar
    Join Date
    Nov 2007
    Location
    Haines
    Posts
    1,308

    Default

    Not cratered. The primers actually still have their round edges. Most of them really didnt come back hardly at all, just enough to be noticed. No signs of leekage around the primers. In fact, all the cases have fairly dirty case necks, as if the neck didn't fully seal up at the throat. I did full length resize them. I worried about high pressure at first too, but I can find any of the signs of high pressure on these cases.
    Born in Alaska: The boundary lines have fallen for me in pleasant places; surely I have a delightful inheritance. Psalm 16:6

  4. #4
    Supporting Member iofthetaiga's Avatar
    Join Date
    Oct 2009
    Location
    Tanana Valley AK
    Posts
    7,217

    Default

    Doesn't sound like the pressure's too high, but that's just internet speculation without some velocity numbers to compare with the book. I agree with marshall tho that RL-15 certainly doesn't need a magnum primer. I'd say load some more up with standard primers and put them over a chrony...
    ...he who knows nothing is nearer to truth than he whose mind is filled with falsehoods & errors. ~Thomas Jefferson
    I would rather have a mind opened by wonder than one closed by belief. ~Gerry Spence
    The last thing Alaska needs is another bigot. ~member Catch It
    #Resist

  5. #5
    Sponsor ADfields's Avatar
    Join Date
    Nov 2008
    Location
    Missing Palmer AK in Phonix AZ.
    Posts
    6,416

    Default

    Sounds like you full length sized them and are running a light load and I agree with Marshall. You increased head space a tad in sizing them and the firing pin drives them forward. They then have enough pressure to grip the chamber wall but not enough to force the head back into the bolt. So now the primer is sitting there un-supported and the pressure shoves it back into the bolt face.
    Andy
    On the web= C-lazy-F.co
    Email= Andy@C-lazy-F.co
    Call/Text 602-315-2406
    Phoenix Arizona

  6. #6
    Member highestview's Avatar
    Join Date
    Nov 2007
    Location
    Haines
    Posts
    1,308

    Default

    I'm starting to think that must be it. I have the dies that were made for semi-autos that size it back a further 2-3 thousandths. I think I'll throw this brass out after I'm done shooting it and neck nize only the next batch. I'm gonna switch over to standard primers, too. If I can find any that is.
    Born in Alaska: The boundary lines have fallen for me in pleasant places; surely I have a delightful inheritance. Psalm 16:6

  7. #7
    Sponsor ADfields's Avatar
    Join Date
    Nov 2008
    Location
    Missing Palmer AK in Phonix AZ.
    Posts
    6,416

    Default

    No need to toss the brass, just load it up with a hotter normal load and they will fire form back out so you can neck size.
    Andy
    On the web= C-lazy-F.co
    Email= Andy@C-lazy-F.co
    Call/Text 602-315-2406
    Phoenix Arizona

  8. #8
    Member marshall's Avatar
    Join Date
    Nov 2007
    Location
    Near Phoenix, AZ
    Posts
    1,814

    Default

    For what ever it's worth. My pet load for my personal 20" 308 bolt rifle is running RL-15 with a 175gr VLD and CCI BR2 primers. I've been able to load both Lapua and Hornady Match cases with the same precision and velocity when bumping the lighter Hornady case by 0.4gr of charge compared to the Lapua. The Hornady case is the same weight as the Winchester, about 167gr on average with the cases I checked. I've ran these over a chrony at 2595fps. The BR2 is a touch slower than CCI200's but ES is slightly improved. Your charge is a touch light in my opinion. The shorter barrel dumps the pressure sooner than a longer barrel allowing a little more charge than a book might suggest with a longer barrel. Careful testing will find your charge.

    Andy summed up what I was trying to say quite nicely. Your comment about gas stains around the neck seems to support that idea.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •