Improvised Weapon Mastery and Improved Critical

[Cuup]

Can the Critical threat range from Improvised Weapon Mastery be increased by the Improved Critical feat?

[Zwordsman]

I would guess by raw no.
Improved critical says "weapon profiecent with" I don't think that improvised weapon mastery makes you profiecent in game terms.
that being said, I would likely allow it, and most gms I know would also.
Though I would imagine they may ask you to specifcy a specific type of improvised weapon if they are feeling froggy.
I dont' think that should be done though; since improvised weapons are aw eird area for endchanting and powering up.

So short answer, RAW I don't think so due to the requirment of proficieny; which exists past just the -4. Since the catch off guard feat just says you don't suffer the penalties, and there are other things that have specific wording like the kitsune (see below). Granted they were made after improvised weapon mastery so you could use that to support allowing catch off guard to count as profiecny so you can get improved crit, and then a lot of other nifty feats.

I think it's perfectly resonable to count yourself as proficient with improvised stuff after catch off guard (and especially after Mastery) and allow all that

but I also build an alchemist who uses a shovel, nails, and other tools as weapons and poison delivery.

Oracle: Reduce the penalty for not being proficient for one weapon by 1. When the nonproficiency penalty for a weapon becomes 0 because of this ability, the oracle is treated as having the appropriate Martial or Exotic Weapon Proficiency feat for that weapon.

[Cuup]

That makes sense, thank you!

[Imbicatus]

Generally double-dipping on threat range enhancers is not allowed. You can't take Improved Critical and a Keen weapon for example. Since an improvised weapon normally has a threat range of 20, Improvised Weapon Mastery is expanding it's threat range. Improved critical explicitly states "This effect doesn't stack with any other effect that expands the threat range of a weapon." It doesn't work.