IMR or H4198?

[mustanggt]

I was inventorying my powder storage yesterday and found I only have 1/2 a pound of IMR4198 left. However I have 3#'s of H4198 and would like to tap some wisdom here and ask if I can interchange data between the two as they are next to each other on the burn rate chart? I suspect I can but I ask because I can't find "H" in any of my two Cast Boolit Hanbooks. I use 314299 sized .312. I really hope I can because it shoots like this: http://castboolits.gunloads.com/attachment.php?attachmentid=31197&stc=1&d=1301970464

[TonyM]

Having used both powders, IMO the H4198 is a bit slower than than the IMR4198... but it's negligible.. I would feel comfortable interchanging load data, as long as you were following the IMR 4198 data..

[mustanggt]

As you can see I will be using 23.0gr of IMR.

[JeffinNZ]

I'm with Tony. H is slightly slower. Still different powders but both made by ADI. In the pressure range you are working in I would happily interchange them.

[Maineboy]

Nice group. I love the 314299 in my Krag. It always performs.

[Just Duke]

Wish you were down here. I have 2 fresh 8 pounders of IMR 4198 and no use for it at the present.

[mustanggt]

Thanks for the replies guys. It's always good to bounce ideas off of other people as maybe what sounds good in your head aint so much when someone else hears it. If I lived closer to ya Duke I'd take one off of your hands. I got more uses than just the Krag for that powder.

[mooman76]

Not sure where I heard it from but they are basically the same powder. One of the two picked up a huge amount of surplus powder and sold it under their own name. It sold so well they decided to market it on their own and copied the formula and continued selling. So they aren't to exact some but basically have the same characteristics and you need to work up as normal of coarse but you already knew that.

[mustanggt]

Hodgdon is the guy that did that after the war with 4895 I believe but H looks different from IMR and usually is a grain apart in their respective loads ie. in my Garand loads I use 47gr of IMR and 46gr of H for the same velocity. Also there was a change after the surplus ran out in the late 60's. I've not seen anything about 4198 in that regard but don't doubt he would use the same formula for sucess. If anyone else can chime in on that little history lesson please do.