hi guys

I normally hang out on the African forum, but could use your opinion.

I started to reload a few .404 rounds, and noticed that when I decanted the tin of S-335 (simmelar but obviuosly not the same as IMR 3031), I noticed a red, rust looking dust coming from it. This dust is much more than I am used to or comfortable with. The inside of the can also looks coated in this (not rust, I think.)

Now the obvious question is, can I still use it (I am very reluctant...). If the powder deteriorated, what caused it to do so, as the tin is perhaps 1 year old?

It may have been very old or poorly stored before you bought it.
If it has a brownish purple haze that floats out of the can it is due to nitric acid formed as the powder breaks down.

Yep it's headed south and will only get worse.

I had some that was only getting started and I loaded and shot a few rounds but wasn't impressed with the results at all.

Best bet is to simply toss it and buy new. As for a cause, temps and humidity are what I ruled as mine. The area I had been storing it was subjected to big swings of both, and I have since moved it all to a controlled environment.

Ambient humidity won't matter if the container is tightly sealed with the cap.

Heat is what kills powder and it's not so much the peak temp as the average temp over a long period of time. Temp swings don't matter a bit, it's only the average temp that matters.

Best way to store powder for long terms is in a freezer but it needs to sit out a day or two to insure the temp difference won't cause humidity to condense on the cold powder!

Rust colored dust is THE classic indicator of nitrocellulose powder breakdown. I've experienced it very rarely over 40+ years of reloading, but it does happen.

Powder exhibiting this charcteristic usually acts as if it is slower and less powerful than it would be otherwise. Thus, it may not be particularly unsafe to use it in terms of what it might do to your gun, but considering the type of game you might be shooting with a .404 it could be unsafe in terms of its effect (or lack thereof) on the animal .

Thanx guys. I will toss the powder, but I did relaod 50 rounds with it (6x45) a month or 2 back. I will test these and maybe pull all the bullets and satrt over.

Karl, pull the bullets and use the powder as fertelizer, get new tin, if you can get it, S335 is out of production, and we wait for Somchem to make new batch. Use S355 or S 365 for your .404 better powder, look at Somchems data, I only use S 365 in my .404.