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357 mag case separation

Discussion in 'Handloading and Reloading' started by tcj, Sep 11, 2016.

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  1. tcj

    tcj Member

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    I was shooting some 357 handloads (158gr SJSP, AA#5, 1466 fps through a 24" barrel) through my Rossi 92 lever action and had a case separation plus one about to separate.

    I only noticed because I was shooting silhouette and saw the small part of the case land next to me :eek:

    po1LHigPj.jpg

    After making sure that the barrel was clear I shot some more without incident but while policing my brass found another that was about to go. These are both Blazer brass and have probably been reloaded 4-5 times.

    Never had this happen with 357 - anyone else?
     
  2. cpy911

    cpy911 Member

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    Never seen that

    I have loaded .38 and .357 for Rossi 92 and revolver. I have reloaded cases many many times. Worse I get is a small split in the case and toss it. Never had a full separation. However, I only load mild loads all subsonic.
     
  3. Walkalong

    Walkalong Moderator

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    Have the headspace checked.
     
  4. ljnowell

    ljnowell Member

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    Was there a cannelure on the case?
     
  5. Catpop

    Catpop Member

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    Wow never saw one of those. All mine split lenghtwise
     
  6. tkroenlein

    tkroenlein Member

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    +1.
     
  7. Walkalong

    Walkalong Moderator

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    Member jfh originally posted this pic of brass that separated under very high pressure.

    [​IMG]
     
  8. 243winxb

    243winxb Member

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    Reduce the powder charge . Had a Marlin 44 mag rifle do that. The lines on the brass show its sticking to the chamber, instead of sliding back. Sticking lets the case stretch and separate. [​IMG]
     

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    Last edited: Sep 11, 2016
  9. Cheesemaker

    Cheesemaker Member

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    This - was there one??

    Or bad batch of brass?
     
  10. Reefinmike

    Reefinmike Member

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    I've seen signs of a case head separation in my 16" rossi 92.

    Brass was starline that had two previous firings. A mild(15.7gr) charge of W296, 18.5gr lilgun and the last reload was 19.5gr lilgun. All with a 164gr PCLSWC. Yes, I worked up from 18.0 to 19.5gr .1gr at a time. There isn't really any lilgun lead data out there so I started with 158gr xtp data, worked through that and beyond max. Lead bullets wont create as much pressure so I wasn't afraid to venture past max. I dont Think I chrono'd anything but the 18.4gr load that I settled on. It cooks along at 2,000fps on the dot.

    In the picture below, you can see a fine line going about halfway around the case. No more of those heavy loads!
     

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  11. au_prospector

    au_prospector Member

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    Look at that.... It split right along those lines in the brass. Looks like some sort of abrasion on the brass right there. Also notice there is a small split on that broken case where the crimp is.

    1466 fps with a 158 grainer has some mustard on it, no? Even in a rifle?

    AA#5 from their published data...
    158 HDY XTP 8.6 1,097 9.7 1,256 33,150 1.590
     
  12. Kp321

    Kp321 Member

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    Looks like the problem is a combination of a rough chamber and excess headspace allowing the front of the cartridge to grab in the chamber instead of sliding. The excess headspace gives it room to do so. Is there possibly a ring in the chamber from 38 specials? I bought a Rossi from a SASS shooter who had fed it a steady diet of Specials. I gave the chamber a good polishing before shooting any 357's through it.
     
  13. tcj

    tcj Member

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    Thanks for the feedback - no cannelure and it only happened with some Blazer brass...most of what I load is Starline. I only shoot 357's in this gun. My powder charge of AA#5 is 9.2gr (fps out of a 6" revolver is 1,108).

    I'll re-inspect all of my brass, thoroughly clean the chamber and get someone to check the headspace.

    FYI - other than the incident with these 2 cases, I've got about 1,900 rounds of this load through this rifle without a problem.
     
  14. The Bushmaster

    The Bushmaster Member

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    243winxb has it.

    You might want to go with Walkalong's too.
     
  15. Grumulkin

    Grumulkin Member

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    The theories on a rough chamber, too high pressure and excess head space have been mentioned. An additional cause could be a sloppy chamber. Any time you resize brass it stretches even in a straight walled case. The more it has to be resized, the more it stretches even in a straight walled case. The brass is thicker at the head so it's not going that way but rather toward the mouth of the case.

    The only time I've had a head separation in a straight walled case was with full house 460 S&W Magnum loads in a T/C Encore.
     
  16. buck460XVR

    buck460XVR Member

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    .357 lever guns, because of the way they lock up at the rear of the bolt and produce bolt movement when fired, are notorious for stretching brass when shot at true .357 magnum velocities/pressures. This is why reloading manuals(Speer for example) state to use only virgin or once fired brass for upper level loads in .357 lever guns. Case separation from shooting brass loaded to max several times in a .357 lever, can be expected.
     
  17. Walkalong

    Walkalong Moderator

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    Yes, lever guns actions flex more than others, so it could be OK on headspace, or maybe on the large end, and then the flex of a stout load, and it all adds up.
     
  18. tcj

    tcj Member

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    Well I just finished inspecting about 500 rounds of brass that have been deprimed & cleaned and found 21 more with subtle cracks. FYI - only a couple of these were felt with the paperclip test; the rest are just barely visible with a bright light and my glasses.

    So, tomorrow I need to go through an ammo can full to check those...dang it.
     
  19. Walkalong

    Walkalong Moderator

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    Might be time for new brass.
     
  20. blarby

    blarby Member

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    Given the cracks on the case necks, i'd tend to agree.
     
  21. ultralightbackpacker

    ultralightbackpacker Member

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    Ohh lord. Thats starline brass. I have around 3k brass from starline, mostly 9mm and 357s, and I can specifically say I have never seen that kind of "separation" on starline. That is by no means a headspace issue. No way, no how.
     
  22. Jesse Heywood

    Jesse Heywood Member

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    You can also see the stretch marks in the right side of the picture. Another item to look for when inspecting brass.
     
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