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Thread: range report

  1. #1
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    Default range report

    I am working up a good all around load for my new mod.70 in 270 win. everything is going well. So far i have about 80 rounds down range. I am using hornady 140gr btsp interlock and h4831sc. Last week 58gr of h4831sc grouped well. this week the same load was all over the place. I would call it human error but every thing else i tried today grouped well. Any insight to whats causing this? photos of the other loads are in the next post
    Attached Thumbnails Attached Thumbnails 58gr,h4831sc,fed 210.jpg   58grh4831sc,f210.jpg  

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    Default range report #2

    This post goes along with the original rage report.Here is 59 gr h4831 sc with fed 210, and 58gr h4831sc with fed 215.
    Attached Thumbnails Attached Thumbnails 59gr,h4831sc,fed 210.jpg   58gr,h4831sc,fed 215.jpg  

  3. #3

    Default

    I don't worry about groups the first 100-150 rounds depending on when I start to see consistency. I just work on cheek fit, trigger and action familiarity. Round count for barrel break-in varies as does severity of change but I use this as my standard.

    There are better minds here than me but this is what popped into my head:

    Did you clean the barrel after last weeks range session? Copper too?

    Did you use the brass fired from this gun to make these new loads? If so, full re-size or just partial/neck size? Does your full-re-sized brass OAL match the OAL of what you used originally?

    Is this the only load that strings horizontally? Was this group fired late in your session when your barrel was hot?

  4. #4
    Member AKHunterNP's Avatar
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    Default

    was there a drastic change in the temperature? Do you have a chrono to check the velocity?
    "...arms like laws discourage and keep the invader and plunderer in awe...Horrid mischief would ensue were the good deprived of the use of them." -Thomas Paine

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    Default

    With the horizontal dispersion your groups are showing I am wondering how windy was it when you were shooting?
    Tennessee

  6. #6
    Moderator stid2677's Avatar
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    Default

    Some common causes for horizontal stringing.

    Wind
    Canting of the rifle
    Barrel making side contact (not properly floated/bedded) will move when hot
    Loose scope or scope mounts
    Inconsistent cheek pressure on the comb
    Load not properly tuned to the rifle
    Placement of the trigger finger
    Breathing or pulse bounce


    Good luck

    Steve

  7. #7
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    Default

    There was a 5-10 mph head wind.
    the barrel wasnt hot and it was cleaned of all copper and residue before the sesion.
    I run a dry patch every 2 rounds and a bore brush with solvent every ten. the barerell is floated well with lots of room. I tried to adjust the trigger pull but the allan screws were covered in glue and im having a hard time cleaning them out. I repositioned the scope and made sure it was good and tight.
    After examining the cases i noticed the neck length is uneven. could this have caused it?
    Well. im going to load some fresh ones and try again.
    I am definatly rusty on the trigger but i didnt think i was that jerky.

  8. #8
    Member marshall's Avatar
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    Default

    I'm leaning towards a loose rear base or ring.

    Uneven length necks will only change the tension and pressure which will affect velocity. That would cause vertical stringing not horizontal.

    Make sure you have a good rest and bag the rear as well, don't rush the shot. If you still have issues it has to be your scope mounts or scope causing horizontal stringing.

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    Default I gotta add one thing

    Excellent posts here. I did find one thing to be true, scope rings need to be trued!

    I bought a ring lapping tool from Brownells to fix a Ruger's rings (they were Godawful from the factory and were literally skinning my new scope!) So, I lap fit those rings. It took a while. The rings used to work loose no matter how tight I tightened them. The contact patch in the rings was awful. After lapping them in to about an 80% fit (it took off a LOT of material!!!) it's all good. Before lapping, you it took a good amount of tightening and never seemed solid (the high points were squishing the scope tube!!!) After lapping, once it got snug, it got tight really quickly. You could tell that it was so much more solid.

    So, then I checked all my other rings. WOW! Some rings, no matter what high dollar name was on them, were terrible! I was shocked.

    It's just a nice thing to do to check your rings fit on the scope, especially a nice scope, before you clamp it down. One of those confidence inspiring, trouble eliminating steps that's not too hard to do. Don't go crazy though! You can also help a pair of rings that needed shimming if you're patient.

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