How do y'all handle load data discrepancies?

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  • Expatriated

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    I'm looking at reloading Sierra GameKing 165 gr (#2145)

    Checking different books show dramatically different load ranges.




    Example IMR4895:

    Lee Book shows starting 42.7 and max 45.5

    Sierra Book shows starting 38.3 and max 41.9



    Viht N550:

    Lee shows starting 44.1 and max 49.3

    Sierra shows 40.7 to 46.7




    How do you determine which book to go with? Do you go with the actual bullet manufacturer's book as the authority? That's what I'm leaning towards.
     

    King31

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    I personally would try to find other sources considering these are so far apart. Is it .308 that you're loading for? I'm sure others could rattle off some numbers from other manuals or find it online from a reputable source.
     

    Expatriated

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    I personally would try to find other sources considering these are so far apart. Is it .308 that you're loading for? I'm sure others could rattle off some numbers from other manuals or find it online from a reputable source.


    Yes, I'm sorry. .308.
     

    Mgderf

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    How old are your load manuals?
    That does seem like a big difference.
    Are you sure you didn't read data for H4198 by mistake?
     

    Bennettjh

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    I checked Hodgdon's site.
    IMR4895 is 42.7-45.5
    No info for N550

    Lyman manual says:
    4895, 38-43.2
    N550, 44.5-48.5, (168 grain).
     

    mac45

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    Manuals vary.
    Sometimes by a fair bit.
    Manual can only tell you the results that publisher, got on that day, with that test rig and those particular components.
    Another test rig might be slightly different, or they may be using different components.
    In this case, just what 165gr bullet is Lee using?
    Dunno
    Was it a Game King.....or just something "close"?
    This sort of ambiguous data is why I try to steer people away from the Lee manual.
    I'll wager if the OP works up to either the accuracy load, or the hunting load in the Sierra manual, he'll be happy.
     

    AllenM

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    When I get big diffences between data sources like this I look online to see what others are loading the bump down a little and load several different loads of 3 rounds each to see which data comes close to my results.
    For that though you need to have or borrow a chronograph.

    It may take a different book then the two you listed to come close to your results. Are you a seasoned or new reloader?
     

    Expatriated

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    I would consider myself moderately experienced. I've loaded thousands of rounds but in very narrow calibers (9, .40 and .25-06). I picked a load that got the job done and stayed with that. I didn't tinker with those. In other words, I have experience reloading but no experience "working up" a load to maximize accuracy.

    And I also don't remember any wide differences like this when studying the options in the above calibers.

    It just seems odd to me that Sierra says don't go OVER 42 with their bullet and 4895, but IMR says to START at 42 with that bullet and 4895. Which one is being overly cautious?

    I am simply looking for a good load for 165 gr Gamekings for hunting deer in my Remington Magpul 700 22" with Vortex 4-16 x 44 HST. The reason I am sticking with the 165 Gamekings is that I have a ton of 168 and 175 Matchkings that I can practice with all day long. The Gamekings should print very very close to the Matchkings from my research so I feel like the Gamekings are the good complement to the SMK.
     

    King31

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    I wouldn't start any higher than 44gr for the Viht N550 based on that data. The Lee Manual echoes what the Vihtavuori site shows which is for a Speer BTSP which is similar to the GameKing. As far as the IMR 4895, I would say start around 40gr to stay safe. If there are no obvious pressure signs increase up to 41gr, then 42gr and finally 43gr. Somewhere in there is likely going to be a sweet spot. I know its over the Sierra data, but several other sources show 42+/- to be good loads. All load manuals have a built in safety factor. Take all this with a grain of salt and make a common sense based decision. I'd much rather being playing with 42gr +/-3gr versus Clays 4gr +/-0.3gr. Happy loading!

    Pulled from gunsandammo.com
    Rifle used in: Custom Remington 700 and Springfield M-21
    165 grain Sierra Game king with 40.7 grains of IMR 4895
     

    Leadeye

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    Reloaded for lots of calibers for more than 40 years, best results for me have always come from averaging out data and starting in the middle. Sometimes the low end loads can be as much trouble as the high end ones.
     

    Fixer

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    I have seen the same thing, but usually they are for 2 different bullets of the same weight just different manufacturers. Try to find one that matches the bullet type you are using. If you can't then start conservatively and work up from there.
     

    dugsagun

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    I always try to match as much info as the manual states. Usually the same brass is number one, primers are next. If i am using the exact same bullet then i will use all the powder charge info available. If i am using a different bullet , i drop one grain from max, if i get up to it. Most accurate loads are not max loads anyway. If i have to pick one source over another, i try to use the most recent bullet makers data.
     

    Expatriated

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    I appreciate everyone’s input. I got sidetracked from the powder by researching how to get the primer pocket crimps out so I can re prime. I tried different methods of chamfering the pocket but I think I’ve just settled in on getting a Dillion 600 Swager. Seems like the best choice for repeated consistency and ease of use.
     

    Broom_jm

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    All load data found in manuals and published from online sources is just a guideline, anyway. I like using the bullet manufacturer's data, when possible, but working with a number of wildcats over the years has forced me to learn how to read the cases, rifle action, and the chronograph readouts to gauge where I'm at with a given load workup. As others have stated, your best accuracy is likely to come a grain or two shy of max, so don't sweat it too much. It's really only a concern if you insist on pushing the envelope.

    I have used a simple countersink bit to remove the hard edge of a crimped primer pockets on thousands of cases. I can't imagine having a dedicated tool for the job.
     

    DoggyDaddy

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    All load data found in manuals and published from online sources is just a guideline, anyway. I like using the bullet manufacturer's data, when possible, but working with a number of wildcats over the years has forced me to learn how to read the cases, rifle action, and the chronograph readouts to gauge where I'm at with a given load workup. As others have stated, your best accuracy is likely to come a grain or two shy of max, so don't sweat it too much. It's really only a concern if you insist on pushing the envelope.

    I have used a simple countersink bit to remove the hard edge of a crimped primer pockets on thousands of cases. I can't imagine having a dedicated tool for the job.

    I've got a little hand swager with bits for large and small primer pockets that I use, but then again I don't load rifle cartridges in large quantities. It's easy enough to do while watching tv or something.
     
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