In one of his books, Col. Nonte goes over powder making. The manufacturer loads the machines with chemicals and turns them on and has no EXACT idea what will come out the other end. Yes, it will be either stick or ball or flake (flattend ball often) or sheets for cutting (I found this in some Europe military)... But nothing EXACT. The major marketers have a "cannister burn rate" and if the batch is close it may be set aside and blended to meet the "canister burn rate" and coated and ... and then packaged for the retail market. MOST POWDER is sold in drums to loaders/factories who have a ballistics lab and the lab works out a load and the machinery is set for that load and a couple hundred thousand rounds are "cranked out." Yes, with safety checks, hopefully.
POINT: from one year to the next, from one batch to the next all powder is not the same regardless of its designation. So "old" 2400 should be loaded with "old" 2400 data or with GREATEST CARE using new data. I think it was Speer #9 book had two 4831 loads for .270 WCF. One was IMR 4831 and the other H4831 and they were 6 grains different...
BEWARE, BEWARE, BEWARE and BEWARE some more. Please. don't blow your head off. Lots of bad press for the rest of us...
The story of rotten powder was explained in Rifleman couple years back. During War WW II, Dupont was asked to speed up manufacture by leaving out a couple of wash steps. Powder was going to be burned shooting at the enemy real soon by all expectations and shelf life was not important. They did. Some powder got into surplus after war. Had acid that would eat a hole in a metal can.
Normal solvents smell like alcohol or acetone (nail polish remover without scent) or lighter fluid. The bad stuff smells like vinegar. And red dust forms from the rotten powder. Dump it on garden or lawn. Nothing to hurt plants. Good fertilizer. Just don't shoot it. Burn rate totally unpredictable. Luck. Happy Trails. Reminds me I have a can of H240 from who knows when. Should open it...
PS. Hodgdon takes questions by email and should be able to advise you. Sold tons of 2400 as H240 surplus over the years.... Before ball powder (110 and 296) took over in .30 Carbine.