Rusty IMR4198


November 19, 2012, 10:53 PM
A buddy gave me 4 lb. of IMR4198. It is pretty old, still in the metal cans. The only cartridge I shoot that has loading data for this powder is .223. I usually load .223 on a Dillon RL550 with the Dillon powder measure using H335. For the IMR4198 , I used a Hornady powder measure off the press since it can shear grains. I loaded a few rounds and they worked OK, so then I loaded several hundred rounds. My powder measure and the funnel over the powder die got coated with rust residue. It is coming from the inside of the can. It was enough to make the powder measure "sticky".

Are there any issues with burning rusty gunpowder?

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November 19, 2012, 11:02 PM
Usually when the rust gets inside the powder can the powder itself is exposed to outside air and usually goes bad. If you already shot some of the powder and it shot well I would say the powder is still good. (or going bad) does the powder smell "bad" or does is still smell like solvent which means it's still fresh?

November 19, 2012, 11:12 PM
It still smells like gunpowder and the outside of the can is not rusty at all.

November 19, 2012, 11:18 PM
Then I doubt the rusty color residue inside is actually rust. It may be the coating of the powder breaking down but that's just a guess on my part. I might not use it if it were mine...

November 19, 2012, 11:31 PM
If you do use it I would not make up a lot of "put away" ammo with it. Also I would watch the canister closely for signs of it deteriorating. Some will say that it is already bad and could catch fire with internal heat generated. If you have some 1 LB cans empty I would put part of each can in them to minimize the heat that could be generated and label the canisters appropriately then keep an eye on it for more damage. Dump it on the lawn if it is deemed bad. I have never seen good powder with red residue of any type in it--just saying.:scrutiny:

FWIW I have 3 old cans of it also with purple label and there is no red stuff in any of mine. I just dumped a bunch out in a powder measure and mixed it around some and poured it back. No residue at all.

November 19, 2012, 11:43 PM
Like I said, I loaded a few rounds and ran them through an AR. No signs of excess pressure with rounds within a few tenths of max. They extracted just fine, and the primers were not flattened excessively. I got a flashlight out and the inside surfaces of the can are coated with a rust colored dust, there is a tiny bit of corrosion on the lip of the cap. Not sure what to think.

November 20, 2012, 06:24 AM
Wisdom says that the propellant may be at a point of spontaneous combustion/decomposition if there is a red powder/dust in the cans. The result is that eventually the velocity will go down or the round will not fire at all if loaded. I have never found any that went bad but others here have and they got rid of the propellant promptly. YMMV

November 20, 2012, 07:33 AM
I would be concerned it is the brownish red dust you get when powder starts breaking down. If it is in a metal can it will also corrode the can. Give it the smell test and a good close look before continuing to use it.

November 20, 2012, 07:41 AM
my two cents..
Is it worth a possible kaboom?

go roto-till it in the veggies or broadcast it over the lawn.

November 20, 2012, 07:45 AM
Yep, if in doubt, toss it out. Makes good fertilizer. I had 6 or 7 pounds of N130 go bad. No dust yet, but a rancid smell. It pained me, but I spread it around in the back yard.

November 20, 2012, 07:48 AM
I'm with JLD:

You could have a disastrous day shooting or a great crop of tomatoes.

Choose the tomatoes.

November 20, 2012, 09:54 AM
I did not shoot this IMR 4895 powder. Did shoot some 4831 surplus with rust many years ago. Groups were not good, & the powder smelled bad.

November 20, 2012, 11:08 AM
Is the smell test accurate? I got a new can, actually plastic bottle, of the same powder, and the smell of ether/solvent in the old can is identical to the new, at least according to my admittedly uncalibrated nose. I think I will use the 200 rounds I already loaded and trash the rest of that can.

November 20, 2012, 01:34 PM
Older IMR 4198 was made in Canada. The newer IMR 4198 is made in Australia.(AR2215) Powder deterioration can be checked by opening the cap on the container and smelling the contents. Powder undergoing deterioration has an irritating acidic odor. (Don't confuse this with common solvent odors such as alcohol, ether and acetone.)

November 20, 2012, 05:39 PM
I have read in DOD and other publications that some powders get a reddish tint when it decomposes. And when powder decomposes it can self detonate according to the same pubs. Best to throw out.

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