Back in “Worst Labyrinth Lord melee weapons”, I wrote:
The war hammer. Is this something like Mjöllnir or a late medieval bec de corbin kind of thing? Is the latter subsumed within pole arm or pick? Why is it two-handed with no one-handed counterpart? Note that dwarfs can’t wield two-handed weapons, but the magical dwarven [sic] thrower war hammer has special rules when used by a dwarf. I’m beginning not to care that the mechanics are suboptimal and unlikely to be picked by a PC. ☺
So, after too little research, I jumped to this conclusion: Mjölnir wasn’t a weapon but a blacksmith’s hammer used as a weapon. Or, if it was a weapon, perhaps it was a throwing hammer. The kind of thing that became the sport of hammer throwing. Or maybe both.
(And that’s ignoring the note I saw that said sometimes Mjölnir was called a club or axe.)
So, the war hammer is your typical bec de corbin sort of thing. (Probably one of the shorter variants with the longer ones being pole arms.) The “War Hammer +2, Dwarven Thrower” is not a really a war hammer but a throwing hammer. Which makes me wonder what the stats for a non-magical throwing hammer ought to be. Same as club or hand-axe?