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WMR powder loads for 375 H&H

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  • WMR powder loads for 375 H&H

    Looking for WMR reloading info for 270gr and 300gr bullets for my 375 H&H I live in Dutch Harbor Where powder is Hard to come by. I got a good deal on 2lbs I have some load data for my 30-06 but would rather waste the WMR on targets with the 375 since it is discontinued now.

  • #2
    No WMR data

    I looked through a bunch of reloading information, but I couldn't find any for WMR in the 375 H&H. It's apparently a bit on the slow side for that application.

    The Winchester Reloading Components Catalog (14th Edition) provides some WMR loads for the following cartridges: 243, 257 Roberts, 26-06, 270, 280, 7mm-08, 30-06 (200 and 220 gr bullets), 300 WinMag, and 338. The only powder Winchester shows for the 375 H&H is W-760.

    In a table of powder "burn rates" at, WMR is listed right between Accurate Arms 3100 and Hodgdon's H4831SC. In the burn rate chart at, WMR is listed at being slower than those two powders, and positions WMR between Vit N560 and Norma MRP. There is also burn rate information at and

    HOWEVER, it is NOT valid practice to try to extrapolate between powders based on burn rates. FURTHERMORE, as odd as it might sound, light loads with slow burning powders can cause unacceptable and dangerous pressure spikes too. So, you can get into trouble with under-charging as well as over-charging.

    Winchester Warns:
    "Do not use burning rate charts as a guide to reloading. Burning rate charts are developed in closed bomb tests. The closed bomb test results merely serve as a very vague guide to the laboratory technician equipped with the necessary pressure testing equipment. Closed bomb charts as developed by a powder manufacturer include only powder of their manufacture. So called "burning rate charts" are usually the result of estimates of where powders would fit if they were to develop a closed bomb test for all brand powders."

    "When powders are used in cartridge cases of varying sizes and shapes, the so-called burning rates can and do vary depending upon the exact set of loading circumstances. One can easily discover this by carefully examining a manufacturer's loading data."

    "Such changes in apparent burning rates come as no surprise to the ballistician who regards closed bomb tests as merely a very crude guide. The same changes, however, have resulted in more than one reloader having trouble when attempting to extrapolate data from a burning rate chart."

    "Reloading data should never be extrapolated and since burning rate charts tend to be misleading, and are often the source of grief to the reloader, Winchester does not suggest the positioning of Winchester [brand] powders on any burning chart."

    Similar warnings are posted on the burn rate chart sites listed above.

    I appreciate your supply problems, but you might be better off to sell that powder to somebody who can put it to better use, and put the money towards the purchase of more appropriate powder(s).

    Good luck.
    In God We Trust.


    • #3
      FORESTAR . Thanks for the info on WMR powder. I have lots of 200gr bullets so will use it on my 30/06 still waiting for my 3rd 375 H&H to come in to my ffl dealer should be here any day. Thanks again DuckToller.


      • #4
        WMR and 30-06

        I can post the WMR/30-06 loading data if you need it.
        In God We Trust.


        • #5
          Forestar. If you have data for 165 and 180 that would be great. Only have 1 load for 200gr at 55.7 gr. Thanks again DuckToller.


          • #6
            WMR and the 30-06

            Here's the data straight from the Winchester booklet (14th Edition);

            For the 200 gr Winchester Soft Point bullet: maximum load of WMR = 55.7 grains, muzzle velocity 2,435 fps, pressure 48,200 psi. Primer: standard (not magnum). Winchester recommends a starting load 10% less than maximum.

            For the 220 gr Winchester Soft Point bullet: maximum load of WMR = 55.7 grains (yes it's the same as the 200 gr bullet load), muzzle velocity 2,380 fps, pressure 51,100 psi. Primer: standard (not magnum). Winchester recommends a starting load 10% less than maximum.

            There is no published loading information for WMR for the 165 or 180 grain bullets in the 30-06. I suspect WMR is too "slow" for those bullet weights. However, if you know anyone with a 300 WinMag or 338 WinMag, they might be able to put the WMR to good use; there is WMR loading data for those calibers.

            Good luck.
            In God We Trust.


            • #7
              Forestar. Once again thanks for your time and info found a new source of powder on the Island. DuckToller


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