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Thread: Case overall length

  1. #1

    Case overall length

    Due to difficulties in getting Sako factory rounds I have started home loading. I loaded some .222 55grn Sierra Gamekings with 21.6grn Viht N130 powder and Federal small rifle primers Case overall length 2.124". I fired 12 rounds at 100yds in a tunnel range with 10 out of the 12 in the bull the other 2 outside but just touching the bull. I then reloaded using exactly the same components the only difference being the overall length 2.122" to my amazement firing in the same tunnel all the bullets were approx 1.5" higher and to the right. I was wondering is this nomal that 2 thousand of an inch difference should give this result.

    Jimbo

  2. #2
    Jimbo

    You're only telling us half the story. How did you measure the OAL? How did you weigh the powder? What kind of dies are you using? Is this new brass you are using, or once fired sourced from your own factory fired ammunition? There's more that could be asked.

    Although folk like us can give some suggestions, I recommend you get a good reloading manual and pick upon some local experienced reloader and refer all your queries to them and get answers face-to-face.

    There's quite a bit to consider when it comes to load testing. I got higher magnification scopes to help with my load testing. Using a consistent set-up for load testing is essential.

    Do keep records of what you are doing, whether it's brass prep, loading ammunition or test results and targets. You quickly forget how you made up a load, or what brass prep steps you took. I find my practices evolve over time and it's useful to be able to look into the archive. I also note kit changes in my reloading book.

    Finally, just like everything else, practice helps, though sometimes reloading seems more of a black art than a science. I guess it's a bit like stalking.

    Good luck. JCS
    Last edited by jcampbellsmith; 25-03-2012 at 13:31.

  3. #3
    Well. The original load/seating depth was .6 grains over maximum. If you seat it deeper, you are spiking the pressure even more and you may be just experiencing rotational drift with the high and right impact shift. Back the load off and see if that helps.~Muir

  4. #4
    Quote Originally Posted by jcampbellsmith View Post
    Jimbo

    You're only telling us half the story. How did you measure the OAL? How did you weigh the powder? What kind of dies are you using? Is this new brass you are using, or once fired sourced from your own factory fired ammunition? There's more that could be asked.

    Although folk like us can give some suggestions, I recommend you get a good reloading manual and pick upon some local experienced reloader and refer all your queries to them and get answers face-to-face.

    There's quite a bit to consider when it comes to load testing. I got higher magnification scopes to help with my load testing. Using a consistent set-up for load testing is essential.

    Do keep records of what you are doing, whether it's brass prep, loading ammunition or test results and targets. You quickly forget how you made up a load, or what brass prep steps you took. I find my practices evolve over time and it's useful to be able to look into the archive. I also note kit changes in my reloading book.

    Finally, just like everything else, practice helps, though sometimes reloading seems more of a black art than a science. I guess it's a bit like stalking.

    Good luck. JCS
    Hi JCS

    The dies are Lee deluxe.
    Cases once fired Sako that had been cleaned in tumbler overnight and neck sized.
    Powder was weighed on RCBS 750 electronic scales.
    Case length including bullet head was measured with a vernier.
    All cases were trim to lenght using Lee case length gauge and cutter.
    Primer pockets were cleaned and uniformed.
    All the usual reloading procedures the only difference being 2 thou less in length.

    Jimbo

  5. #5
    Quote Originally Posted by Muir View Post
    Well. The original load/seating depth was .6 grains over maximum. If you seat it deeper, you are spiking the pressure even more and you may be just experiencing rotational drift with the high and right impact shift. Back the load off and see if that helps.~Muir
    Hi Muir

    The load data I have taken from the Sako 55grn Gamehead. Depending on which manual you use there are many differing max powder loads older manuals seam to give higher powder loads than current manuals all very confusing.

    Jimbo

  6. #6
    Quote Originally Posted by Jimbo 30 06 View Post
    ...Case length including bullet head was measured with a vernier...
    There is significant variation in the profiles of bullets, especially lead tipped bullets, so measuring to the ogive is a better tack to take, using something like the following:

    http://www.hornady.com/store/Lock-N-Load-Precision-Reloaders-Accessory-Kit

    See - Lock-N-Load Bullet Comparator

    Good luck. JCS
    Last edited by jcampbellsmith; 25-03-2012 at 14:40.

  7. #7
    To be honest there is probably far more than 2 thou in difference in the length of the bullets you are loading. Personally I figure anything within 5 or even 10 thou of the length I was aiming for is good to go.

    In these situations I have found that it is much more likely the shooter, rather than the load, is at the root of the problem. For example maybe your head was hitting the stock in a slightly different place or the rifle was supported differently or... All these things can easily add up to a 1.5 inch movement of the group. I've been there and chased moving groups and so on myself and in general it was probably me at fault rather than the rifle or the load.

  8. #8
    Quote Originally Posted by Jimbo 30 06 View Post
    Hi Muir

    The load data I have taken from the Sako 55grn Gamehead. Depending on which manual you use there are many differing max powder loads older manuals seam to give higher powder loads than current manuals all very confusing.

    Jimbo
    This is from VV's 2012 web site which list max at 21.0 grains. But no matter: That you use the charge weight you do is up to you but I'm just saying that when it's loaded to max already, any change in depth to the shorter side will increase pressure. Depending on twist and speed, you could get an increase in POI and a shift to the right or left. Just speaking out loud, not throwing stones.~Muir

  9. #9
    Quote Originally Posted by Muir View Post
    This is from VV's 2012 web site which list max at 21.0 grains. But no matter: That you use the charge weight you do is up to you but I'm just saying that when it's loaded to max already, any change in depth to the shorter side will increase pressure. Depending on twist and speed, you could get an increase in POI and a shift to the right or left. Just speaking out loud, not throwing stones.~Muir
    Hi Muir

    I was not being critical only explaining where I had taken my data from I was very greatful for your responce.

    Many thanks Jimbo

  10. #10
    Cool. I speak American so I'm often misunderstood....~Muir

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