300 WSM Loads (Rookie Alert)

Discussion in 'Reloading' started by skookum, Jun 26, 2013.

  1. skookum

    skookum Well-Known Member

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    I have recently been able to start making handloads for my McMillan 300WSM. I found several recomendations for 70-72gr of RL22 but i then read in a manual that there's a max load of 67gr with 190gr bullet. Can anyone help me clear the mud with this? I loaded a box with 70 gr of RL 22, do i have a box of potentially dangerous fireworks or will I be ok to shoot them? I'd hate to have to pull the bolt out of my face after shooting..
     
  2. baldhunter

    baldhunter Well-Known Member

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    All rifles are different.My 300 WSM has a short throat and I would not be able to shoot your load.The best advice I can give you when working up your load is,load some more at lighter charges like 65.0grs and work your way up to the 70.0gr loads you have.Never,ever start with a max load!Mine is maxing out with 70.0grs of Reloader-22 with a 165gr bullet so I'd be in big trouble shooting a 190gr bullet with that load.
     

  3. CogburnR

    CogburnR Well-Known Member

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    Never use an internet load without reducing considerably, book loads also reduce 5%.

    Rifles can vary considerably in the powder charge they will work with without excessive pressure. Especially custom rifles with long throats,etc.Even starting book loads in some may show pressure. Also, powder lots vary somewhat.

    I would back down to 3 grains below the book at least and go up from there in 1g increments. Once you find some pressure back off 2% or more.

    Keep in mind temperatures-loads developed at say 50 degrees may be dangerous at 80 degrees.
     
  4. Beluebow

    Beluebow Well-Known Member

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    You have been giving very sound advice.Start low and work up and find out what the pressure limits are in YOUR RIFLE.Be safe and buy a bullet puller.:)
     
  5. lloydsmale

    lloydsmale Well-Known Member

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    Mine too. Its starting to show pressure signs at 69 grains of re22 and a 165. Could be the guy that gave you those loads shoots a long action with the bullets seated way way out there. Even then it sounds like a pretty hot load.
     
  6. skookum

    skookum Well-Known Member

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    Once again the voices of reason and knowledge have spoken, thank you gentleman. I will be pulling the bullets off and trying again. I managed to find IMR4831 powder as well so i have some work and testing to do.
     
  7. alaska

    alaska Well-Known Member

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    Reloader 17

    I have found Reloader 17 to be most excellent in the 300 WSM
     
  8. skookum

    skookum Well-Known Member

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    I tried 66gr of RL22 with 190 gr sierra and barely shot MOA, the rifle is capable of half that so its back to the drawing board, i bought an OAL gauge and i think that will help. waiting on sportsman's to get some H4350 and maybe some different slugs as well.
     
  9. alaska

    alaska Well-Known Member

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    I consider the 190gr alot of bullet for the 300 wsm case

    Suggest 180 or better yet 165/168

    For powder

    RL 17 tops in vel
    RL 19 a close second
    W760 duplicates win loads
     
  10. lloydsmale

    lloydsmale Well-Known Member

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    Re: Reloader 17

    17 IS THE POWDER in my buddys wsm but mine just doesnt do that great with it. I get my best groups with h4350 and h4831sc. Mine seems pretty primer sensitive too. I does ok with about any standard primer, real good with fed match mags and terrible with cci or ww mag.
     
  11. alaska

    alaska Well-Known Member

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    Imr 4831 also good
     
  12. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Skookum, do you understand the concept of starting low and working up?

    Reloading manuals are good references but you will differences between them, sometimes significant differences but they are a good starting point.

    That said, there is very little to no published load data available for many powder/bullet combinations. What I do in that case is search for all the online data I can find and look for trends to find a good starting point. I usually like to start at least 10% below known max charges and work up in .5 gr or full gr increments (depending on case capacity). For the WSM, I use .5 gr increments.

    As you work up, look for pressure signs. That is a tricky art, so I would recommend reading everything you can find on pressure signs. Knowing the burn rates of various powders and how they act with particular bullets and cases helps a lot.

    Once you find what your max working charge is, then you can experiment with different bullet seating depths and load charges to find which are most accurate in your rifle.

    I found RL17 to give very good velocitiess in my 300 WSM. My max was 67.5 gr fro 180 E-Tips. I would recommend starting @ 61 if you try it.

    I have to disagree the WSM does not shoot heavier bullets well. A lot depends on whether or not you are shooting a long or short action and how deep you seat the bullets, etc. I got 2935 fps with 210 Bergers and RL17 in my 300 WSM.

    Hope that helps
     
  13. alaska

    alaska Well-Known Member

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    Reloader 17 very good powder in the 300 wsm the new Berger elite bullets should be most excellent in the 300 WSM
     
  14. TBuckus

    TBuckus Well-Known Member

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    Yes, they may be dangerous.
    I know every gun is different, but Right out of the boxm I was shooting sub MOA with RL22 and 168 gr sierra's.
    I'm now working up loads for it with Barnes bullets. We'll see how they do.