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What causes this bulge???

Discussion in 'Handloading and Reloading' started by CMV, Feb 11, 2012.

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  1. CMV

    CMV Member

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    Loading some 9mm I noticed this today. Mixed HS brass, 115gr Hornady FMJ, 1.122 OAL. On some cases I see/feel the shape of the bullet base on one side of the brass only. Like when the bullet is seating it's going in on an angle & not being set straight?

    Is it normal?

    Is it something I should correct?

    Is it something I need to worry about?

    If it's something I can/should correct, how?

    I'm thinking maybe I'm not opening up the case mouth enough with the expander die? If I measure before & after OD at the mouth I get .0055 difference so maybe only opening the mouth 5 & a half thou isn't enough to let the bullet get straight on its way in sometimes & it does this? All I can think of.

    Anyway, these pics are of the same round. First one you can see the 'bulge' but it's hard to get a good representation in a photo. 2nd pic is same round rolled 180° & no visible bulge.

    [​IMG]

    [​IMG]
     
  2. Tomcat47

    Tomcat47 Member

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    Is it normal? ....... It happens sometimes

    Is it something I should correct? ...... I Do!

    Is it something I need to worry about? ...... I would!

    If it's something I can/should correct, how? ......... Take your seating die apart and clean it, it could have gunk in it which in turn starts the bullet into case crooked and possibly starts even worse than the end result.

    Also make sure your cases are sized right, and trimmed square and no burrs!

    You can pull some of those crooked ones apart with Kinetic hammer, and do some investigating. Mark some up with a Sharpie...go through the process (less powder charge or primer installation) and see what is going on.

    Yon can always pull them back apart, but marking them up and going through the process... you find the problem.
     
  3. rcmodel

    rcmodel Member in memoriam

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    Normal.

    It is a sign of good case neck tension.
    Which is necessary to prevent bullet set-back and high pressure during feeding.

    Thicker brands of brass will show it more then thinner brands.

    Fuggedaboutit!

    PS: It can also be caused by not flaring the case at all to allow the bullet to start straight.
    You don't want to flare much for jacketed bullets, but you want enough to get them started in the case straight by hand.

    rc
     
  4. bigedp51

    bigedp51 member

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    Its normal especially with carbide dies, the cases were sized smaller than the diameter of the bullet. Seating the bullet enlarged the case "except" the area below the bullet. (wasp waisted)
     
  5. mizer67

    mizer67 Member

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    If it's only on one side of the round, it's called runout. What that means is the round is going in crooked, canted to one side.

    The best way I know to cure runout is not to cause it in the first place. You can try more belling. If that doesn't correct your issue, you can try the Redding competition seating die. It is spring loaded and helps straighten the bullet prior to seating.

    If it's 360 degrees, then it's fairly normal and that "Coke bottle" shape is cause from neck tension in the brass.
     
  6. joed

    joed Member

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    As others said it's normal. As long as the round chambers without problem you're good to go. When doing cartridges for auto I always take the first one off the press and drop it in a barrel to make sure all is good. I'd hate to do 1000 that don't fit.
     
  7. rcmodel

    rcmodel Member in memoriam

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    I'd much rather see that then not have enough neck tension to prevent set-back during feeding!!

    The wasp-waist look won't blow your gun up.
    Telescoping rounds will, or might.

    A 9mm is a tapered case, and if you can't see the base of the bullet, it means not much is touching it except the case mouth!

    rcl
     
  8. gamestalker

    gamestalker member

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    9mm isn't a straight walled case, so being that it is a tapered wall the bullet will often buldge on one side, and occasionally all the way around. Belling the mouth more won't eliminate it, or even reduce it for that matter. More bell is only going to cause your mouths to get over worked, resulting in premature splitting.

    But the buldge your seeing isn't unusual nor is it a concern to any extent. As long as the round chambers normal your good to go.

    I realized many years ago that belling the mouths really isn't necessary unless you are loading non jacketed bullets, which I don't. In fact, I don't ever bell any of my brass, and it hasn't caused me any problems. I chamfer the inside of the mouth just enough for the bullet to seat without shaving. In my opinion, the advantage to seating like this is two fold. First of all, I'm not working the mouth at all, which provides me with 100% unaltered neck tension. The other advantage is I don't ever have to worry about head space being effected by inadvertant over crimping to close the belling.

    The 9mm, and a number of other auto loading cartridges head space at the mouth, so if someone were to over crimp it would interfere with head space, which could cause potential FTF's, ruptured cases, bullets can get pinched during firing which can raise pressures on an already pressure sensitive cartridge, and it distorts the bullet. And in the event a case gets over belled or the crimp isn't closed sufficiently, it can cause neck tension issues or cycling issues.
     
  9. Walkalong

    Walkalong Moderator

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    Looking good.
     
  10. Striker Fired

    Striker Fired Member

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    Technically it's not right, something isn't perfectly straight with each other or holding/feeding square & stright. Ideally the shell holder should be square, straight and hold the case tight, the bullet seater die should be square and perfect in alignment with the case as it enters it. Thats the perfect world, where everything is exactly the same size,length,ect...

    The real world has a little slop because things are not perfect,so in order to work with all differences,things need to move.This is the result.You can take extra time and make sure everything is clean and perfectly square and in as close to perfect alignment as possible(probably a good idea anyway) and it will help,but is it worth it? For the most part , no. As long as they come out REASONABLY aligned you'll be good.

    It is hard to get every round to come out even ,especially on progressives. I have taken the time and got true rounds using my single stage, but not on any progressive. That time I was testing some 45ACP rounds and with 10 straight and even,the other 10 "offset"more to one side,I could not tell in accuracy between the two. That was my only comparison,but I'm sure others have tested it also.
     
  11. jcwit

    jcwit Member

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    Once again rcmodel hit it on the head!
     
  12. 243winxb

    243winxb Member

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    Make sure your bullet seating stem fits the bullet nose correctly. Use a die that bells & expands the case mouth. Seeing the base of the bullet is ok if 360 degrees. Not on 1 side. IMO.
     
  13. Bovice

    Bovice Member

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    Not sure what dies you are using-I use Hornady. My seating dies have an alignment sleeve in them to help keep the bullets straight. You might want to consider them if you're worried.
     
  14. CMV

    CMV Member

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    I'm using Lee carbide dies. FL resize, powder-through expander, and the seating die. FCD installed on 4th spot on ring but I'm not using it.
     
  15. cfullgraf

    cfullgraf Member

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    The bulge is a common occurrence in reloaded 9x19. If you have some concerns remove the barrel from your pistol and see if they chamber before ruining them with the FCD die.

    The barrel of your pistol is the best case gauge ever for your reloads.

    As an aside, the case walls of a 9x19 are straight, they just are not parallel.
     
  16. jcwit

    jcwit Member

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    Looks like a plated lead bullet, right? If so what does it mic. at? I'll bet its just a thousandth oversize which would be correct for a lead bullet, plated or not.
     
  17. Tomcat47

    Tomcat47 Member

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    +10 on Hornady! I love there die sets. Have a lot of Lee, but I got Hornady for my most popular calibers.
     
  18. CMV

    CMV Member

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    115gr FMJ Hornady. They mic @ 0.3555.
     
  19. jcwit

    jcwit Member

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    Well that blew that theory.
     
  20. sugarmaker

    sugarmaker Member

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    Not serious. Misaligned bullet on case when seatiing, or lots of room in the seater die (lee dies), not enough bell to get the bullet on the case straight, having the wrong shaped seat plug on your die.

    The round will shoot fine, no effect on the target as the ammo is still better than the gun.
     
  21. Naterater

    Naterater Member

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    I get this all the time. NORMAL.
     
  22. Tomcat47

    Tomcat47 Member

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    I too see it as a "Normal" issue reloading 9mm,

    However as the OP stated, he sees it one sided sometimes
    (Bulge on one side) Not what one likes to see......I will take them back apart myself.

    This can usually be remedied by cleaning the dies and making sure the cases are sized right and they are square and free of burrs.
     
  23. Walkalong

    Walkalong Moderator

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    Only get worried if one side has none and the other has a lot. Other than that, no worries.
     
  24. bds

    bds Member

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    I get very slight bulging when seating Winchester .355" jacketed FMJ but (due to sharp flat base of the jacketed bullet) if the bullet gets tilted during seating, case will show more pronounced bulging on one side (see bottom picture). Like many posted, even the cases with bulging on one side shoots fine.

    Typical case bulging with 115 gr FMJ (same amount of bulging all around the case)
    [​IMG]

    More pronounced bulging showing on one side of case due to bullet tilt during seating
    [​IMG]
     

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  25. rcmodel

    rcmodel Member in memoriam

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    Crooked seating?
    Not always.

    More bulging on one side then the other can also be caused by non-symmetrical brass.

    If one side of the case mouth is thinner then the other side, you will get more bulge on the thin side, because it is easier for the bullet base to expand it then the thick side.

    rc
     
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