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Thread: Imr4198 / H4198

  1. #1
    Member Alangaq's Avatar
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    May 2007
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    Default Imr4198 / H4198

    these two powders sit side by side on my burn rate chart, but I have little to no experience with them. are they interchangeable? can the same load data for one, be substituted for the other safely? or are we talking apples and oranges here? are they close enough that if you drop back 15% you can use the data and work up a load? I am asking because I have a load that calls for H4198 and all I have is IMR4198.
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  2. #2


    My experience with these two powders all has to do with the triple duce (222).It always takes about a half grain less of the IMR 4198 than H4198 with any given bullet weight.

    Hodgdon now owns IMR and if you go to you can point and click your way into the loading data for any given round and they will list suggested loads for both of these powders with bullet weight of choice.

  3. #3


    You should be fine dropping back to a lower starting load, then working up. I haven't really noticed any difference, but then I'm not one to push book max on my loads. I'd check the load your looking at against the book max in the sources EKC has noted and proceed accordingly.

  4. #4

    Default NOT Sure

    In their older (original forms and cans) they didn't load exactly alike in my 222 or 221. But in their newer forms ie: manufactured by Hogden they may well be identical. But, the best way is to start at a 10% reduction and work towards max in your rifle.
    My best loads seemed to come from the IMR powder though.
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  5. #5
    Join Date
    Jan 2005


    I don't think they have ever been the exact same powder, unless today with the consolidation of the companies, but they are very close in burn rate. They should at least be treated as if they are form different lots of the same powder. If you look at loading manuals that use both in the same application you some times see a slight difference in loading. They are close but reduce back to starting loads when switching.

    There are several powders by different companies with the same name/number. IMR 4350/H4350, IMR4831/H4831, IMR4895/H4895, and there are others. Also AA 3100 and IMR 4831 are very similar but with all these droping back to starting loads is a good idea.

    There are so many powders out now and they are hard to keep up with. I know a fellow who was told to use 48.0 grains of RL-7 for his 45-70. He found AA#7 and thought that was what he had heard. Well, 48 grains of AA#7 and a 400 grain bullet cost him a good lever rifle and two fingers. The bolt stayed in the gun though.

    With the IMR vs H powder above the difference is very slight but it is always good to study it for a while before jumping in with both feet.
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