So finaly came homen with some IMR 4831, what could I expect to be differences between the H4831 that I have normally used. More or less grains? Newby reloader.
Thanks!

Depending on what calibre you are loading but IMR will reach MAX pressures with 3 to 5 grs LESS powder than H4831. Be very carefull my friend

That is why they print loading manuals. H is slower than IMR. Read them before loading any ammo with your new powder.

The two powders as so dissimilar that it is unfortunate that they share the same numerical designation.

H4831, particularly the current version imported from Australia, is significantly slower than IMR 4831. Current H4831 is even slower than original surplus 4831, much to my surprise. The "H4831" version made in Scotland was a tad faster than original surplus 4831, but still slower than IMR 4831.

IMR 4831 is only marginally slower than IMR 4350 and is a better substitute for 4350 than it is for H4831.

You will need to completely rework your loads for H4831, starting over much lower, if you attempt to substitute IMR 4831.

Thanks for the replies, I have talked to a buddy who uses both and he gave me some tips. I will also look at the reloading manuals I have.

Stonecreek is correct.

There are many powders labeled as H4831.
Their burning rates vairy so widely, that I do not trust using any loading data, from any source as you just never know exactly what H4831 was used, as even the source might not actually know.

And I can say I have used a lot of the original surplus 4831 powder, many years ago. It and the newer H4831's and I use IMR4831 as well, are all great powders, but you need to ne careful IMHO when starting out with new loads...

As others have said imr4831 is faster burning than H4831. The plusses are it in my rifles gives higher velocity and greater accuracy than H4831. Not a lot but some. Negatives It is temperature sensitive which H4831 is not.

quote:

I will also look at the reloading manuals I have.

Ya think?

Would you even be asking these questions if the powders had completely different names? They are after all different powders, made by different companies on different continents. It's like asking if R-7 is the same as Accurate #7.

Thanks Steve, dont hold back, tell it like you think.

quote:

Originally posted by 24mileboy:
Thanks Steve, dont hold back, tell it like you think.

I would but tell you what I really think would get me banned even on this forum!