243 Compare IMR 4350 to H4350 charge weights

Discussion in '6PPC, 6-6.5x47, 6XC, 6 Rem, 243' started by urbanrifleman, Sep 25, 2017.

  1. urbanrifleman

    urbanrifleman

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    Tested IMR 4350 in my rifle with moly Berger 108s and found a sweet node at 40 to 40.5 grains with Lapua brass and CCI 200 primers.

    There seems to be a lot more emphasis on H4350 over the IMR version among the shooting community. Are they identical burning rates? Or not?
     
  2. Rob01

    Rob01

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    Not identical. Close but not the same. H4350 is favored as it's very temp stable and the IMR version is not as stable. That said as long as you keep an eye on the temp and load you should be fine with the IMR version.
     
  3. urbanrifleman

    urbanrifleman

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    Do you find that H4350 is slightly faster?
     
  4. urbanrifleman

    urbanrifleman

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    I am thinking Reloader 16!!!
     
  5. dstoenner

    dstoenner Silver $$ Contributor

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    I have seen posted by a reputable source that if you have a good load with H4350, increase it by 3% for IMR 4350. I tried that in my 260 Rem and did not find IMR to shoot as well as H4350 with equal charges or +3% charges.

    David
     
  6. Mozella

    Mozella

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    I'm collecting components for a 6.5mm Creedmoor, so I'm no expert but since I can't find H4350, I too need an alternative. I've decided to start with Reloder 16 based on what I've read. Apparently tests show it to be even more stable than H4350 and it produces a tad bit faster MV for the same charge weight. RL-16 isn't readily available either, but at least you can find it in a few places. As far as I can tell, there ain't no H4350 on the Internet market.

    H4350 is the hand's-down choice for those shooters using the 6.5 Creedmoor or similar cartridges in major matches. I wonder if that is because it's better than RL-16 or is it just because they've developed a great recipe for H4350 over the years and have no compelling reason to switch to the much newer RL-16?
     
  7. onelastshot

    onelastshot Gold $$ Contributor

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    Two completely different powders, IMR is a faster burning powder and you'll find when checking reloading manuals that there will be as much as 3-4 grain differences in maximum charge weights, depending on caliber. The only thing they have in common are the numbers 4350 in their name. For your 243, shooting 107 grain bullets the maximum charge as reflected in Speer's reloading manual for IMR 4350 is 39.8 grains while the maximum charge weight for H4350 is 37.5 grains.

    Two different powders manufactured by different companies in different countries.
     
    Last edited: Sep 26, 2017
  8. Milo 2.0

    Milo 2.0 Gold $$ Contributor

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    No doubt H4350 has one big cult following, it's a powder I will never shoot, not fighting the masses for it. I've heard guys say, on almost all cases, do a load with 4350 to fall back on, one time it was a 6.5 saum, I'm like just buy retumbo and be done.
    RL16 should be perfect in your 6.5, I'm shooting it in a 6 creed and like it, open the hole up, should only get better.
     
  9. Rob01

    Rob01

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    Never used RL16 but have been using H4350 in the .243 since 2004 and in my Creedmoor since 2008. It deserves it's reputation as it works great in the Creedmoor and that is why it was used by Hornady for the first 4 years of it's loads. I continue to use it in both as I have it and I have loads that shoot great for it. No need to change.
     
  10. Rob01

    Rob01

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    Those are some pretty low max loads. I use 42.6grns of H4350 with my 105s and the .243. When I shot the 115s I used 42grns. Always good to work up for safety though.
     
  11. urbanrifleman

    urbanrifleman

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    So, you just said by charge weights the IMR is SLOWER.
     
  12. onelastshot

    onelastshot Gold $$ Contributor

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    I agree regarding max load numbers, I'm simply quoting posted loads.
     
  13. Rob01

    Rob01

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  14. Rob01

    Rob01

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    Oh I know. I was just mentioning that they were low from actual loading.
     
  15. onelastshot

    onelastshot Gold $$ Contributor

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    I can't post my loads, I'm what you would call a barrel burner, most of my loads are two to three grains above listed maximums. I always shoot for accuracy, but if you can obtain accuracy and still push the bullets a few extra hundred feet per second all is good.
     
  16. Rob01

    Rob01

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    I am the same way but don't mind posting my data but always say to start low and work up.
     
  17. onelastshot

    onelastshot Gold $$ Contributor

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    I stand corrected, and rightfully so, you make mistakes and invert numbers and powders when you try posting when you've only had two hours of sleep.
     
  18. urbanrifleman

    urbanrifleman

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    R16 is definitely a bit faster than IMR 4350. The kernels are also much smaller. I will work this up to the accuracy node and see how it does. I think that many of the people posting their 243 loads using both 4350 loads are way over SAMMI pressure limits. As the max loads from the manufacturers are very consistent and most everyone is going several grains over those...
     

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