h-4198 & imr 4198 powders the same?

[dewcrew8]

just asking if you can use h-4198 powder when it calls for imr 4198 the burn rates are imr#59 and h-4198 #60? .thanks for your input!

[NoSecondBest]

Call Hodgdon and ask them. I did and they had no problem answering the question. I don’t want to say it’s OK, but based on their answer to me I’m using them the same for my application.

[Marco Califo]

No. They are not the same and are not interchangeable.
Hodgdon publishes separate data for each here: http://www.hodgdonreloading.com/data/rifle

[NoSecondBest]

Like I said, call them directly. They’ll answer the question.

[Rimfire5]

H4198 is an extreme powder (temperature insensitive) and IMR4198 is not.
If you call Hodgdon, ask them what they spec how many fps change the two experience from 0 to 125 degrees F. You will be amazed.

H4350 (an extreme powder that I use for my 6.5mm CM) changes 4 fps over that 125 degree change. IMR 4350 changes 67 fps over the same range.
If you are shooting near the extremes of that temperature range with IMR4350, load tables don't mean much if you don't adjust for temperature. You have to adjust the charge to account for the effect of temperature.

[Unclenick]

IMR 4198 is made in Canada at the General Dynamics Valleyfield plant. H4198 is made by ADI in Australia, where it is known as AR2207. When one of the ADI powders is substituted for IMR4198 due to the unavailability of production capacity for the original, they have substituted AR2215 in the past (this was in one of their old MSDS sheets). Why the substitute isn't used for H4198, I don't know, but the two ADI powders must be very close. You will find, owing to the temperature stabilization and different processes involved, H4198 and IMR4198 will be closer in some bullet and powder and cartridge combinations than in others. So you want to look at differences listed by Hodgdon in their data for your particular cartridge.

[TX Nimrod]

Regardless of whether they are “the same” powder or not, the prudent handloader knows that different lots of the same powder can give different results and should be accounted for. The difference may or may not be much, but a faster lot substituted in a maximum load could put the load over the safe limit. Always drop the charge a bit when changing lots (or substituting H4198 for IMR4198) in maximum loads.

True handloading (as opposed to simple reloading) isn’t for those faint of common sense. Thank goodness the firearm makers build a large safety margin into their products....



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[Double K]

In small 22 caliber cartridges I've found H4198 to be slower than IMR4198 and they are definitely not interchangeable.
Ditto what rimfire 5 said and consequently I wouldn't bother with IMR4198 unless you already have some.

[dewcrew8]

Thanks for all your reply's and info ! I was trying to use up what my dad had bought many moons ago! the imr4198 is newer (2010) than the hodgon , It's in the old paper round can from around the 70's also unopened . It says it was made in scotland!

[Double K]

Powder becomes weaker with age, if you don't have chronograph find someone that does to check velocities while looking for pressure signs.

[Marco Califo]

Sniff your newest powder. Then open and sniff the old container. If they smell very different or acrid, decomposition may have begun. Look at it too. Powders do not have an unlimited shelf-life.

[Unclenick]

Dewcrew8,

That does sound old. Probably from before Hodgdon hooked up with ADI and probably made at the same plant that used to make the Brigadier stick powders, which were very similar to the IMR stick powders in many respects. Better quality, IMHO, than the stuff made on this continent as, like Vihtavuori, they used more expensive cotton fiber-based nitrocellulose, so it burned cleaner. Unfortunately, that plant burned down and was never rebuilt.