Having the darnedest time finding this, can anyone point me to a rule source for it?
No, but I believe in the case of a weapon sized for a medium creature it counts as a tiny object. I think the general rule is you subtract two size categories from the creature size an object is designed for to get its size (for weapons and armor).
But I can't recall where I got that from.
The only exact definitions I've ever been able to find are from 3.5 or earlier. (Edit: For an inexact match, there's the table under the animated object entry in the Bestiary.)
The weapon thing is . . . odd. I wouldn't expect a brass knuckle for a Medium creature to be the same object size category as an earth breaker for a Medium creature. Using the animated object example, I'd call the brass knuckles Diminutive and the earth breaker Small.
The weapon thing is . . . odd. I wouldn't expect a brass knuckle for a Medium creature to be the same object size category as an earth breaker for a Medium creature. Using the animated object example, I'd call the brass knuckles Diminutive and the earth breaker Small.
I think it was more a general guideline.
Like I said I can't recall where it came from.
It may have also been a case where light weapons went down a size and two handed went up a size.
The animated object chart is a good Paizo basis though.
A candelabra is tiny and a chair is small.
How did I miss the section on weapon sizes? Thank you, that at least gives a baseline for me to rule from.