338wm opinions please

Discussion in 'Reloading' started by Pecco22, Aug 25, 2019.


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  1. Pecco22

    Pecco22 Well-Known Member

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    My father has a winchester rifle chambered in 338wm. I have been helping him reload for it so he can hunt moose with it. Hes using 225 nosler partitions with federal large magnum primers. We've managed to get his his rifle shoot an ES of 3 and SD of 1.7.... With a powder charge of 72.5 of RL19, however his groups are like 5" at 100. Do I assume my next step is adjusting his seating depth?
     
  2. HARPERC

    HARPERC Well-Known Member

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    Seating depth isn't going to fix 5" groups. Something in the rifle, or optic is way off.
     
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  3. Pecco22

    Pecco22 Well-Known Member

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    Yeah that's why I'm so confused with it. Seems like great es and sd yet the absolute best groups its put out were 1.5" at 100
     
  4. HARPERC

    HARPERC Well-Known Member

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    Which stock is it? We had similar issues with the cheap synthetic stock in a .338. Way to flimsy IMO.
     
  5. 257Tony

    257Tony Well-Known Member

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    Try a box of factory ammo, to some other know good load that the rifle likes. If that shoots like crap too, then start at the bottom and work your way up. Meaning, check for the action binding in the stock, then on to pulling and remounting the scope. That fixes most problems I've found. If it persists, then you'll need to try a different scope.
     
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  6. Pecco22

    Pecco22 Well-Known Member

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    His scope is relatively new leupold. It is a synthetic stock. Factory ammo.....shoot around a 2 or 3 inch group at best.
     
  7. MagnumManiac

    MagnumManiac Well-Known Member

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    Small ES/SD doth not make an accurate load EVERY SINGLE TIME.
    You need to FIND the most accurate load, then check ES/SD and adjust powder charge in .2-.3gr and fine tune before seating depth.
    I have loads that print 5 shots into ONE HOLE @ 100yrds.............BUT, ES/SD is in the order of 100fps.
    Barrel oscillation with those loads just happens to coincide with each other, nothing magical there, but at 500+yrds, the vertical is woefull.

    Seating depth is the last thing to tune, but seldom matters in hunting rifles with short magazines and long throats.

    Cheers.
     
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  8. jjmp

    jjmp Well-Known Member

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    How's the trigger pull ,if it's heavy it'll for sure affect the groups fired . Recoil can be stoughter then more people want to admit , I myself have struggled with my 338mag ,until I learned how to roll with the recoil ,a good recoil pad don't hurt either . Use a shot case and dry fire that rifle to check it's trigger poundage , a past recoil shield helps when shooting off the bench , good luck & have a Great hunt !!! Cheers !
     
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  9. Mike 338

    Mike 338 Well-Known Member

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    I have a 338 WM that shoots best with a big jump (.225"). You should definitely do a rough seating depth test ala Berger method. In load development, this is the second thing I do, right after finding my maximum powder charge weight. Close to lands yeilds 2-1/2" groups. Big jump yields sub moa accuracy. Problem with the 338 WM is that your shoulder can't hold up to a bunch of testing!
     
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  10. Pecco22

    Pecco22 Well-Known Member

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    I appreciate everyone's help. We looked over his rifle....rear ring on scope was loose and wont tighten up.....so hes off to buy better rings.....may finally be able to get this thing shooting right.
     
  11. Mike AVM

    Mike AVM Well-Known Member

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    I shoot a couple of 338 WM's. I've had my best luck with RE17. Try the Barnes 225 TTSX or the 215. My factory stock Ruger Safari shoots both sub-MOA. I won't tell you how much for liability but I think you'll find with most of these bullets and RE17, you can load near lead bullet levels.
     
  12. CO_Guy

    CO_Guy Well-Known Member

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    Excellent to find the problem. What I found out about any type of troubleshooting is 1) put out of your mind that you know what the answer is (some folks just can't do this) and 2) purely look at what the data is telling you. In your case, it certainly helps by starting to look for the obvious and loose screws are pretty obvious.

    I find that the 338 can be a great all around platform, with the ability to be loaded with quite a weight range.
     
  13. deerhunter64

    deerhunter64 Well-Known Member

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    Love the 338 Mag. Not a huge fan of the recoil but it hits with serious authority. I get pretty good groups with the 225 Accubonds . Had a bad mishap quite a few years ago while deer hunting in a serious snow fall. There was a buck standing directly behind the buck I shot at. Both were broadside maybe 5 feet apart. It looked as if there was only one buck when I took the shot. 250 yards later I came across the buck I shot only to seed there was another buck behind him just as dead as the first one. The 338 packs serious power. The bullet passed through both bucks and thankfully there was not a third or fourth one lined up as well.
     
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  14. DUSTY NOGGIN

    DUSTY NOGGIN Well-Known Member

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    paralax on Leopold should be covered .. check that

    i would also try a copper bullet ..

    my best power for 338 was imr4831