Issue with .356 125gr SNS Coated

Discussion in 'Caliber Talk: Ammunition, Reloading, and Shooting ' started by pscipio03, Apr 14, 2019.

  1. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Ran out of my normal Bayou Bullets 124 gr coated, so picked up some SNS coated 125gr .356 bullets from Dillon when I was in the store.
    Same load that I normally use for my Bayou, but had 4 squibs out of 50 rounds.
    Bayou measured out to 1.1585 OAL and the SNS measure out to 1.1530
    Crimp is .378 on the Bayou and .3765 on the SNS.
    Just did a plunk test (as I normally always use a case gauge not a barrel) and in my STI barrel, none of the SNS passed the test, but all of the Bayou ones I had left over did.
    The SNS sticks out maybe 1/8 of an inch further than the Bayou.
    Also, noticed that I had a TON of unburnt powder all over my arms with the SNS.
    I'm at a loss. Not sure if it's because the Bayou has the lube ports (not sure what they are called) and the SNS don't, but my other reloads using Bayou like the 115 and 147 gr don't have the lube ports and they function just fine.
    Any ideas? The single beulet is a Bayou and the two are SNS.
    Also, using 4.2gr Bullseye powder.


  2. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Should say that I always weigh my powder the first 10 rounds and about every 100 do another 5 or so.
    When I got home today I tested 20 and all had the proper powder throw. So, not thinking it’s a problem with powder not dispensing
    Dub likes this.

  3. gun_fan111

    gun_fan111 Well-Known Member

    Mar 23, 2014
    Are you saying that you have not adjusted your seating die? Just left everything set as with original bullet?

    Were squibs hard to remove or came out easy? Where in the barrel were they stuck?

    Two things I can think of:
    - new bullet is shorter and because of that leaves more volume in the case
    - new bullet’s diameter is too small for your barrel

    I have only been reloading for a few years myself.
  4. Dave Jessee

    Dave Jessee Well-Known Member Supporting Addict

    Dec 31, 2014
    If you are getting squibs I seriously doubt it has anything with your bullets. Has this powder been exposed to moisture or heat? Lube ports have nothing to do with anything other than just being ports.
  5. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Powder is no issue- same container I'm using for some 200 LSWC for with no issue. Also, loaded up other 124gr earlier with it with no issue. Also, I adjusted the depth to get me similar results.
    As odd as this may sound, I think it's the barrel. Did a plunk test on 3 other pistols' barrels and they all accepted the new ammo with no problem, to include a custom Kart. Entirely possible the ogive is causing it on an improperly reamed barrel (this is a new STI). Going to take another pistol out (which I probably should have done in the first damn place) and shoot 30 or 40 through it to see if the issue happens with a different gun. If not, well, mystery solved.
    If it is the barrel, and it's too narrow, then it would take a hot load to clear the barrel. While 4.2gr of Bullseye isn't powderpuff, and undersized barrel could block it. Especially if the hopper throws a 4.1gr and that's just the right amount to get it stuck instead of clearing.
    Kept the last bullet- going to measure it for a barrel slug.
    Dub likes this.
  6. gaijin

    gaijin Well-Known Member

    May 18, 2015
    Sounds like you're not generating enough pressure with the SNS bullets to reliably ignite the powder. This due to additional case volume.

    Shorter OAL.
    Hotter primer; SRP or Magnum SPP.
  7. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Mystery is solved. I took measurements last night and the barrel is out of spec. Getting the RMA today to send it back.
    The only ammo I had shot in the pistol previously was some Blazer 124grs. Since the plated lead in the Blazer is much softer than the hard cast coated, it pushed them through.
    Odd occurrence.
    Dub likes this.
  8. gun_fan111

    gun_fan111 Well-Known Member

    Mar 23, 2014
  9. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Underchambered and barrel was tight.
    I think it is less an issue with the barrel being too tight, and more the chamber issue. Have a suspicion that in the process of going into battery, the brass was stopped short, and the bullet was forced forward separating the two almost completely. Meaning, pressures dropped to almost 0. Would explain the unburnt powder but spent primer.
    Dub and gaijin like this.
  10. gun_fan111

    gun_fan111 Well-Known Member

    Mar 23, 2014
    Interesting. Please update us when you hear back from the manufacturer.
  11. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Already did. Was pointed the right direction and reached directly out to the master gunsmith for them. Apparently they had an out of spec reamer and a few barrels escaped (under a dozen) and I must have just been lucky enough to get one of them.
    Getting a RMA soon and it's going back.
    Dub and gun_fan111 like this.
  12. Old Sea Dragon

    Old Sea Dragon Well-Known Member

    Feb 10, 2018
    Glad to see that this is getting resolved. Good luck
  13. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Just confirmed. Took a quick run to the range on my lunch break with a different gun. Ran the remaining 80 rounds with 0 issues.
    Barrel problem. Grumble.
    Waiting on the RMA.
    Dub likes this.
  14. Old Sea Dragon

    Old Sea Dragon Well-Known Member

    Feb 10, 2018
    A few smiths on this forum have stated that finish reaming chambers solves a lot of customer problems. Perhaps some machinists overuse it trying to stretch a buck and end up with undersized dimensions due to the worn tool.
    Dub likes this.
  15. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    I assume like with any tooling, stacked tolerance add up.
  16. cdhbrad

    cdhbrad Well-Known Member

    Nov 21, 2011
    I shoot the "cone" version of that 125gr SNS bullet. I only crimp it to .379 so you may want to ease off the crimp a bit. If you didn't adjust the crimp from Bayou to SNS, interesting that it went from .378 down to .3765.

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