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Need help/advice - primer seating

Discussion in 'Handloading and Reloading' started by garth64, Jan 29, 2010.

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  1. garth64

    garth64 Member

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    I've been reloading 357 Mag cartridges for my revolver and I'm having a big problem with misfires; about 30%- 40%. I originally thought it was the prime system on my turret press so I bought a RCBS hand primer; I'm still getting the same results. I have no way to measure the seating depth; I'm just relying on the tool. I'm using Magtech small pistol primers. Any advice is welcomed. Thanks.:banghead:
     
  2. Walkalong

    Walkalong Moderator

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    Make sure the primers are below flush in the pockets.
     
  3. garth64

    garth64 Member

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    I normally do that by feel; they all appear to be below being flush, thanks.
     
  4. EddieNFL

    EddieNFL member

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    Are you seating to the bottom of the pockets? You should be able to "feel" them bottom out.

    Are you over seating (crushing) the primers?

    Does this specific firearm have a problem with factory loads or loads with different primers?

    Recent trigger job or spring replacement?

    Any possibility the primers were contaminated.

    What did I forget, guys?
     
  5. garth64

    garth64 Member

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    I do feel the primers bottom-out; I also apply a lot of force, I may be crushing the primers; the revolver is fairly new (about 1000 rounds through it), it's a S&W 627; no trigger job or spring replacement; thanks.
     
  6. jcwit

    jcwit Member

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    Sounds like you're crushing the primers. Seat one and gently remove it and look at the compound pellet under magnafaction. The anvil 'the three pointed thing' should be pushed just flush with the cup without damaging the pellet.
     
  7. garth64

    garth64 Member

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    That's good info, something I didn't know, thanks!
     
  8. EddieNFL

    EddieNFL member

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    The S&Ws I own are all more than 20 years old, so I don't know if this still applies.

    If the FP strikes look shallow, check the spring tension screw. It may have backed out.
     
  9. garth64

    garth64 Member

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    Thanks EddieNFL; without any manuals right now, is this screw easily accessible, and how would you adjust?
     
  10. Walkalong

    Walkalong Moderator

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    It takes a lot to crush a primer to the point it won't fire. It can be done, but it takes a lot of pressure.

    Eddie had a really good suggestion about checking the tension (strain) screw. Is the gun new to you? Does it fire factory fodder OK? Weak aftermarket spring?
     
  11. garth64

    garth64 Member

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    The gun is factory new, and I've never had a factory round misfire.
     
  12. The Bushmaster

    The Bushmaster Member

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    SEAT the .... primer!! Don't be afraid of setting it off. You won't!! It must be just below flush with the case head. You will be able to either see it or feel it. BUT SEAT THE DAMNED PRIMER...

    I bet that if you struck the primer a second time it would go off...

    DO wear safety glasses when ever you are reloading.......
     
  13. garth64

    garth64 Member

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    Hey Bushmaster, is it a good idea as indicated before that as a test case to look at the anvil as being just flush with the cup. I've seated the primers in all cases by squeezing the manual priming tool extremely hard with the result that the primers are below flush with the case head, I'm just not sure if I'm crushing the primers, if in fact, that could cause this many misfires; thanks.
     
  14. 243winxb

    243winxb Member

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    Gun Problem? The hammer should be able to lift about 4 lbs. if i remember corrrectly. New gun, lube it so the hammer has no drag. Break Free CLP.
     
  15. fractal7

    fractal7 Member

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    If you can't tell if you're seating them flush or not try this: Put a primed case into a pair of calipers like you were measuring case length and hold the rimmed end up to a light. Since most calipers are thinner than the primer pocket if they are just below flush you should be able to see a small slot of light right where the primer is. Not terribly scientific but usually how I check mine.
     
  16. Sam1911

    Sam1911 Moderator

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    This is in the gun, not your technique. Seating primers just isn't rocket science and really doesn't require a micrometer. If you press until it stops -- it's SEATED. That's it.

    Either your gun's strain screw is backed out causing too little tension on the mainspring, or the hammer is hanging up and not getting enough speed on the fall to deliver enough energy, or you need a heavier mainspring.

    The screw is in the lower front of the frontstrap of the grip. (Depending on what grips your revolver wears you may have to remove the grips to see the screw.) If you put a well-fitting screw driver on it and tighten it firmly, it's tight enough. If it wasn't tight, there's your problem.

    If it lights all factory primers (try several brands), it could be that the MagTech primers are much harder than normal. On the other end of the spectrum, Federal brand primers are very soft and will light off pretty consistently even in guns running light springs. If it lights off all factory ammo, S&W is probably going to say that it's within specs.

    If it isn't consistant with factory ammo, S&W may take it back, replace the mainspring, and even polish up the hammer channel to help it move faster.

    If it is still an issue, you could replace your factory mainspring with a Wolff "Type 1" spring and see if it improves anything. The Type 1 springs aren't heavier, but they do feel different/better than stock. Just might work better, but for $12 they could be worth a try.

    -Sam
     
  17. garth64

    garth64 Member

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    Thanks for all the advice!
     
  18. rcmodel

    rcmodel Member in memoriam

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    Then a 30%- 40% mis-fire rate with reloads almost has to be defective primers.

    1. Check the strain screw.

    2. Change primer brands.

    * A properly seated primer should be below flush.
    * The anvil should be crushed into the primer pellet slightly to "pre-load" it.
    * The firing pin should make a good dent in the primer.

    If you are doing all that and still getting mis-fires, you have a bad batch of MagTech primers.

    BTW: A severly crushed / flattened primer is generally more sensitive, not less sensitive.

    rc
     
  19. garth64

    garth64 Member

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    Thanks rcmodel; I just bought some CCI primers which I'll be trying next, but I will first check the strain screw.
     
  20. Sam1911

    Sam1911 Moderator

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    Sounds like a plan. Hoever, be aware that CCI primers are on the harder end of the spectrum. The "up side" is that, if you gun will light off CCI primers, it will light off anything that's made properly.

    As rc said, certainly could be a bad batch from MagTech.

    -Sam
     
  21. garth64

    garth64 Member

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    I'll post a follow-up as soon as I get some results; thanks to all.
     
  22. rcmodel

    rcmodel Member in memoriam

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    If a factory stock S&W 627 won't light CCI primers, or any other good brand of primers, you need to send it back to S&W for repair!

    rc
     
  23. The Bushmaster

    The Bushmaster Member

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    Garth64...I just went into my reloading/gun room (Man Cave) and pressed a primer as far as my Lee Auto Prime II could. The primer ended up .012" below the flush. Loaded it in my S&W Mod 10. Pulled the trigger and it went off.

    I've seated primers sideways (oops), which definately crushes them. Out of curiosity, loaded them in one of my revolvers. Pulled the trigger. Guess what? They went off...
     
  24. garth64

    garth64 Member

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    It looks like I either have a batch of bad primers or my strain screw is out of adjustment, thanks.
     
  25. floydster

    floydster Member

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    For the last 54 years I have seating my primers with authority and never have a problem,a few miss fires along the way, but few and far between.
    Floyd
     
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