Reloading 9mm: 0.356" or 0.357"?

Discussion in 'Reloading' started by cysoto, Mar 2, 2010.

  1. cysoto

    cysoto Gone Shooting!

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    For those of you reloading 9mm bare lead bullets...
    If given a choice of bullet diameter, which do you prefer: 0.356" or 0.357"? Why?
     
    Last edited: Mar 2, 2010
  2. Boxerglocker

    Boxerglocker Jacks #1 Fan

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    I was loading 147g LFP's at .356 no problems, for my LWD barrel.

    The deal is your suppose to measure you actual barrel bore first "SLUG" the barrel. To ensure you get a bullet diameter that gives the optimum gas seal. Here is a website with a little info: http://www.lbtmoulds.com/measurebore.shtml

    I have read though that slugging the bore for most newer 9mm barrels is just a futile exercise as the manufacturing processes for said barrels are pretty in tune. That 0.356 is the norm. After doing so I never bothered and was happy with the results of the bullets I used after getting the powder charge where I wanted it.
     

  3. DEADLYACCURATE

    DEADLYACCURATE Senior Member

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    Recommend .356
    Why never used .357
     
  4. dudel

    dudel

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    Depends on the barrel. Not all 9mm barrels are cut the same. Slug the barrel, then pick lead that is .002 larger (as a rule of thumb). .001 larger for jacketed.
     
  5. fredj338

    fredj338

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    Actually Dudel, it's only 0.001" larger for lead & groove dia for jacketed. Always been like that. Can a lead bullet 0.002" larger work, maybe. Slugging the bore is desireable but I have had great luck in dozens of handguns w/o doing it & just shooting 0.001" larger lead bullets.:dunno:
     
  6. Colorado4Wheel

    Colorado4Wheel

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    No reason to go bigger then you need to. It will just make getting the larger lead bullet into the chamber more difficult. What barrel are you using?
     
  7. coal

    coal

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    .356"... because that's what lead 9mm are supposed to be.
     
  8. cysoto

    cysoto Gone Shooting!

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    I have been using the 0.356" in a factory Glock barrel and I haven't any trouble with them.

    I wasn't planning on switching to the 0.357" unless there would have been an excellent reason to do so. It's just that I have recently noticed that some bullet manufacturers offer both options and I wasn't sure what reason they had for this.
     
  9. fredj338

    fredj338

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    9mm bore sizes are all over the place. SOme are as small as 0.353" som as large as 0.358". The only way to know, drive a soft/oversized slug through the bbl & measure it.
     
  10. chris in va

    chris in va

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    My bore slugs out to .355. I've had ZERO luck with .357 boolits I cast, and someone gave me some 38 special .358" to try out, which shot a lot better with less leading. Might want to consider the same.
     
  11. HAMMERHEAD

    HAMMERHEAD

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    My .355" bore .38 Super shoots great with Meister 130 grain RNFP cowboy bullets sized at .357", so does my S&W .38 Special, nice to share bullets between guns.
     
  12. PCJim

    PCJim Senior Member

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    I would suspect that the data provided in most reloading guides is for a .356 projectile in a standard .355 bore. If you plan on trying the larger diameter .357 projectiles without first slugging your barrel, take prudent precautions and back off the powder a bit. The larger diameter will produce greater resistance, thus greater pressure for the same powder charge.
     
  13. fredj338

    fredj338

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    One thing I have learned about shooting lead bullets is powder does matter. If you aren't having luck w/ you fav jacketed pwoder, then shifting to something else can have a marked diff in accuracy. The old standby for lead bullets is Unique for a reason. If it won't shoot lead bullets o/ Unique, it probably won't shoot lead bullets.:supergrin:
     
  14. Patrick Graham

    Patrick Graham Footlong Jr.

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    My experience with .357" diameter 9mm lead bullets is limited to a Lee TL356-124 six hole bullet mold that I bought several years ago.

    Initally some of the holes were throwing .354" diameter bullets so I lapped them to .357", I wanted .356" but that didn't work out.

    Anyway, the bottom line is that I loaded up some of those .357" bullets with a crimp of .378" and pulled them just to see if they would be swaged down during seating.

    My Fowler calipers measured the pulled bullets between .355" and .356", or .355" with a small 5 in the lower right corner.

    I probably could have sized out of this by flairing more in stage two of my RL550 but I decided to just sell the LEE mold after I lucked into an RCBS 147gr 9mm mold.

    Bottom line was I failed at .357" diameter 9mm.
     
    Last edited: Mar 4, 2010
  15. HAMMERHEAD

    HAMMERHEAD

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    Good point. One powder I'm starting to like a lot for lead bullets is IMR SR 7625. It's a single base powder that burns cool, has good load density, and seems to work best in the smaller cases. Not overly fast burning either.
    The VV powders are always winners if you can find/afford them.
     
  16. fredj338

    fredj338

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    When I got my BHP, couldn't get 125grLRN to shoot w/ several powders. Went to a 124grLTC & Unique, like magic. Guns are funny things.:dunno: