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i really need to have this explained to me

Discussion in 'Handloading and Reloading' started by mypps, Jul 21, 2009.

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  1. mypps

    mypps Member

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    okay, so here we go. i recently started to reload, 9mm for now, but more later. anyway, my question has to do with the measuring of powder charges. i have looked at several books and each one calls out for different amounts for the same load. i am using winchester 115 gr. fmj bullets, imr 700x powder and mostly winchester brass. depending on where i look, i see different measures. i am only making target rounds and don't need to go crazy with it. is there some rhyme or reason to the varrying numbers? who should i believe? i still have all 10 digits and would like to keep it that way. thanks.:confused:
     
  2. ar10

    ar10 Member

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    Pick one or two, then start at the lowest published load, (I don't think they're that much different). then work up the load. I use the Hornady, Speer, and Nostler manuals and all three vary a little.
     
  3. paradox998

    paradox998 Member

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    I have found the same problem. Based on my somewhat limited experience, I usually go with a lower end load to start with and work up. Also, I give a little more weight to the values supplied by the powder manufacturer.
     
  4. liljohn

    liljohn Member

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    The differences in load data between loading manuals exists because there are variations in all components involved in measuring pressures. Some of the variables are:

    case thickness (affecting volume and neck tension)
    bullet shank length (affecting volume and neck tension)
    bullet mass
    Bullet diameter
    powder burn rate (it will vary by lot)
    cartridge OAL
    pressure barrel dimensions (chamber, bullet, throat, etc)
    pressure measuring methodology
    ambient temperature and humidity
    elevation (affecting air density)

    The effect any one of these variables might be slight, but all together could result in a variation of 10% or more between compiled results of two independent test cases.
     
  5. mypps

    mypps Member

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    i've looked at the different loads. one source says 3.3 to 3.7 max, and another says 3.3 to 5.0 max. i made a few rounds at 4.0 gr. using the latter source of info. i'd hate to have to take them apart. but if i must i must.
     
  6. Steve C

    Steve C Member

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    Manuals and on line data come from 2 different sources, the companies that manufacture or market powder and the companies that manufacture bullets. The data from the bullet manufacturer is developed using their bullets while the data from the powder manufacturers are a bit more generic.

    All the data sources tell you the maximum charge they suggest and you need to be knowledgeable enough to use proper load development and reduce that maximum load by 10% for your start load and work up, testing each incremental charge increase, to no more than the maximum load while looking for potential over pressure signs and finding the "sweet spot" that shoots the best in your pistol or rifle. Stop and back your load off a bit if pressure signs appear. Other manuals will print a start load, essentially doing the math for you.

    By working the load up from the start load you will maintain a safety margin despite using different components than the data was developed with.

    This is data from the Hodgdons on line data. While your 4.0gr load is a bit warm it should be fine. I've looked through several data sources, old and new, and none of them listed a 700X load at 5.0grs, are you sure you where not reading 800X or perhaps a 90gr bullet?
     

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    Last edited: Jul 22, 2009
  7. rg1

    rg1 Member

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    Loading 9MM with it's small capacity case depends a lot on your bullet seating depth too. If you seat your Win 115 fmj's to a long overall length pressure will be less than if you seat them shorter. Here's some data from Midway's LoadMap series. They seated the bullets very long for 115 grain fmj's. They seated to 1.165" with the Win 115fmj, used Win sp primers and Remington cases. With IMR 700X powder they started at:
    3.3--898fps--19500 psi
    3.5--941fps--21600 psi
    3.7--984fps--23800 psi
    3.9--1027---25900 psi
    4.1--1070---28100 psi
    4.3--1113--30200 psi
    Midways 9MM LoadMap does warn that seating them shorter than their tested length increases pressure. I listed the loads just to show the pressure increases with increases in powder. That's what I like about Midway's Loadmap series of 4 books. They printed them in .44Mag, 45ACP, 357Mag, and 9MM. Guess the profit margin wasn't there as these are the only ones they made and they are not available anymore. They tested about 10 different powders for each bullet and tested a lot of different companies bullets. For instance with 9MM 115 grain bullets they tested 17 different 115 grain bullets. You can get a comparison of different bullets with the same powder charge and which creates more pressure. Just for your info. With the 1.165" oal and the above components they said Caution going above 4.3 grains of 700X powder and 4.5 as a Maximum load to not go over. Now if you load them shorter then pressure will increase.
     
    Last edited: Jul 22, 2009
  8. Marlin 45 carbine

    Marlin 45 carbine Member

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    I've noticed variations in powder data will vary due to test barrel length also, from maual to manual that is. ever so slightly maybe but there may be.
     
  9. ar10

    ar10 Member

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    The other issue is each of the manufacturers use different weapons when they test the loads. And not all guns are created equal. A good example is the .308 that I load all the time. Mine are for the AR10B while they, (manufacturer) is using a bolt gun. To complicate matters they all test fire different bolt guns. I know I cannot use their exact load info for a semi auto.
     
  10. mypps

    mypps Member

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    this was in a book from sierra that i found at cabelas. well more of a binder than a book. that book lists 5.0 gr. as the max recommended load. and i'm using fmj not gdhp. i've been setting the rounds all at 1.160", the same as the WWB that i usually shoot with. so to be safe, should i pull these rounds and redo them with less powder? i'm using a walther pps, which isn't really recommended for use with +p rounds anyways, making me question my measures.
     
  11. loadedround

    loadedround Member

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    AR10 has basically nailed it. Even a new out of box pistol or rifle of the same make and caliber will show different signs of pressure with a given load. Majority of all new firearms are mass produced , and therefore the wear on the factory's chamber and/or barrel reamers will affect that firearm's maximum chamber PSI, depending on how worn the reamer is, and hence it's maximum load capilbilities. Speer did a study on this a few years ago and published in one of their loading manuals under the title "Why Ballisticians Get Gray". :)
     
  12. ranger335v

    ranger335v Member

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    "The other issue is each of the manufacturers use different weapons when they test the loads."

    And there is your answer. No component change we can make to a book load is as important as that one.
     
  13. showmebob

    showmebob Member

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    I load Berrys RNDS 115 gr with 4.2 gr of 700X and still get 2% FTE. Any less of a charge and the FTE rate goes up. One caution with 700X. It doesn't measure well at all in my powder measure (+/- .2 grains) so be very careful to avoid an overcharge if you are loading near maximum.
     
  14. myg30

    myg30 Member

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    Working "UP" a load means start at the low end and go up from that.
    As others have said, your sweet spot can be at the low end of the charge.
    My .40 cal loads are at the low end and duplicate factory ammo and I didnt need to re-adjust my red dot site. POI is the same ! That was my goal.
    Why waste more powder ?

    Be safe, Mike
     
  15. mypps

    mypps Member

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    well, i've been trying different loads, working up from the low end and am now almost at the max load i found at IMR's website(3.7 gr.). the gun will fire, but most times it won't strip a round out of the mag. works fine with my store bought target stuff, but not my 3.6 gr. reloads. could that extra 0.1 make the difference? sometimes the round wil chamber, sometimes it comes part way out of the mag and jams. this never happens with the store stuff, so i can rule out the gun. i'm gonna go by the chart someone above posted and try 4.0 gr. and see where i am. thats in the middle of the charts range. maybe i'll do some at 3.8 gr. as well.
     
  16. lykoris

    lykoris Member

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    sounds like it is too light a load.

    I can look at my manuals and tell you what each one says given what you are using

    metallic cartridge reloading - 3rd edit

    distinction being it's a 115 grain JHP rather than your 115 FMJ bullet

    gives for IMR700-X a starting load of 4.0 grains and a high of 4.5 grains
     
  17. loadedround

    loadedround Member

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    MYPPS:
    FYI, the current Speer #14 manual shows 4 gr of 700X powder with a 115 gr jacketed bullet 4.0 gr as the STARTING LOAD. With this information, I woould not hesitate shooting your already loaded ammo, but would be watching for obvious pressure signs. :)
     
  18. lykoris

    lykoris Member

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    Speer 14th edition gives for a

    115grain TMJ RN bullet and 700-X(I don't know this powder but presume they mean IMR700-X)

    a starting load of 4.0 and a max of 4.4

    COAL of 1.135"
     
  19. lykoris

    lykoris Member

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    loadedround beat me too it:))

    I will check the other manuals but it seems your 3.6grain loads are a bit on the light side
     
  20. lykoris

    lykoris Member

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    Lyman 49th edit

    for a 115grain JHP with an OAL of 1.09 gives

    3.1 for a starting load and 4.5 as a max for "700X" - again I presume they mean IMR700-X

    they seat it deeper 1.09 hence the lighter starting load
     
  21. lykoris

    lykoris Member

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    Lee 2nd edit

    115grain jacketed bullet

    IMR 700X 4.2 to 4.7

    with min. OAL of 1.110"
     
  22. lykoris

    lykoris Member

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    Sierra 3rd edit

    115FMJ COAL 1.100"

    700X - 3.8 (starting load) to 5.0(Maximum load)

    my Vihta manual only has their powders but it seems you are on the light side of things.

    What is your COAL on the rounds you have made up with 3.6grains of 700x ?
     
  23. lykoris

    lykoris Member

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    I suggest you take the barrel out of your handgun and use it as a case gauge to test the rounds you have made before you bring them to the range.
     
  24. mypps

    mypps Member

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    i'm using winchester 115 gr. FMJ. i'll make up some at 4.0 and head to the range this week and give them a shot. so what book does everybody like for reloads? i've been meaning to get a book for home.
     
  25. hydraulicman

    hydraulicman Member

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    different bullet profiles create different pressure. find a middle ground between your books
     
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