Cordite
Do a google search, and you will get about as much info as possible on Cordite. It seems that thyere is more than one version, for different applications.
The size of the sticks seems to regulate the burn rate. The bigger, (thicker), the slower the rate.
As for it being fast, if you think about it, a burn rate of 4198 is about perfect for a catridge such as the 303 British.
About the Hood. The Bismark's Naval Rifles were no better, or worse, than any other modern Capitol Ship of that era. In fact, they were 15 inch, not as large as the 16 inch Rifles on all post treaty Battleships that the USA built.
The Hood was not a true Barttleship. It was a concoction that was designated a "Battle Cruiser". Sure, it had the Rifles of a Battleship, but lacked the substantial armor that a true Battleship possessed. The weak deck armor allowed the plunging shell from the Bismark to penetrate all the way inside one of the Barbettes. True Battleships are desined with armor that will withstand what ever the ship can dish out.
Remember, any burning material, if contained, will sooner or later build enough pressure to cause an explosion. That ignited cordite contained inside the armored Barbette was one huge pressure cooker. When everything let go, the ship literally split in half, and went down in minutes.
A good example of how much punishment a true Battleship can absorb, just look at the Bismarks last minutes. Crippled, and unable to manuver, it withstood countless hits from the British Battleships Rodney and Prince of Wales. Sure, it's none armored structures were blown to bits, but as recent evidence shows, the Germans actually scuddled Her. If they could have got it to a home port, She probably could have been rebuilt........jackie