How close do these two interchange? I just got a nice batch of H4895 from a friend that has decided to quite using it...not sure why. It was a recently purchased lot. I've used IMR4895 for years. Any help would be appreciated. Thanks. Gary.

Don't mix the two powders together, otherwise they're the same IN TERMS OF LOAD SPEC.
They do, according to Hodgdon Data Manual #26 (1992) produce slightly different velocities and pressures.

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H 4895 meters way better than IMR. Get a manual but I think H is a little slower.

Gary, the IMR 4895 and H 4895 are about as interchangable as any two powders made. Some of the older reloading manuals suggest that they are virtually identical in performance.

Having said that, I think it might be prudent to back off a little on your loads just to be safe when you first try any switching from one to another. (Just a few shots with the powder backed off slightly.)
Some current reloading manuals even suggest doing this when switching to a new lot of the same powder!

I doubt that you will see any difference in these two powders. In my own personal experience, I have always gotten better accuracy with the H 4895 version. That is the favorite powder for use in my 22-250 rifles.

Hope this helps, R F

As posted, at one time they were considered to be the same. In fact, they were both surplus powder. I would not mix the two canisters but recently I couldn't get any H4895 locally and so thought I would try some IMR 4895. Same load (not max) shot to the same point. What this means to me is I would use them interchangably but if I were motoring my rifle top end, I would do a bit of work up and, being sort of paranoid, when I switched, I'd just have to shoot a couple of sighters just to make sure.........

Thanks, gents....I appreciate your responses. Gary.

I agree that these two powders are usually pretty close. I haven't had any experience with the current production H4895 and am not sure who it's made by or where, but older lots of H4895 behaved closer to IMR 4895 than nearly any other two powders of the same number and specs.

I've used a lot more H4895, but recently had only the IMR version available (an older lot of DuPont manufacture) and was pleased with the results.