AoMF, Impact, Monk - Success?

[Kazumetsa Raijin]

Here's a tricky question for you:

Let's say I'm a Monk that relies only on his Improved Unarmed Strike. If I acquired an Amulet of Mighty Fists, and enchanted it with Impact, would the weapon property Impact actually apply, and would it stack with Strong Jaw?

Amulet of Mighty Fists:
This amulet grants an enhancement bonus of +1 to +5 on attack and damage rolls with unarmed attacks and natural weapons.

Alternatively, this amulet can grant melee weapon special abilities, so long as they can be applied to unarmed attacks. See Table: Melee Weapon Special Abilities for a list of abilities. Special abilities count as additional bonuses for determining the market value of the item, but do not modify attack or damage bonuses. An amulet of mighty fists cannot have a modified bonus (enhancement bonus plus special ability bonus equivalents) higher than +5. An amulet of mighty fists does not need to have a +1 enhancement bonus to grant a melee weapon special ability.

Improved Unarmed Strike:
(Feat Entry)You are considered to be armed even when unarmed—you do not provoke attacks of opportunity when you attack foes while unarmed. Your unarmed strikes can deal lethal or nonlethal damage, at your choice.
(Monk Entry)A monk's unarmed strike is treated as both a manufactured weapon and a natural weapon for the purpose of spells and effects that enhance or improve either manufactured weapons or natural weapons.

Impact:
This special ability can only be placed on melee weapons that are not light weapons. An impact weapon delivers a potent kinetic jolt when it strikes, dealing damage as if the weapon were one size category larger. In addition, any bull rush combat maneuver the wielder attempts while wielding the weapon gains a bonus equal to the weapon's enhancement bonus; this includes all bull rush attempts, not only those in which a weapon is used, such as Bull Rush Strike, Shield Slam, or Unseat.

Strong Jaw:
Laying a hand upon an allied creature's jaw, claws, tentacles, or other natural weapons, you enhance the power of that creature's natural attacks. Each natural attack that creature makes deals damage as if the creature were two sizes larger than it actually is. If the creature is already Gargantuan or Colossal-sized, double the amount of damage dealt by each of its natural attacks instead. This spell does not actually change the creature's size; all of its statistics except the amount of damage dealt by its natural attacks remain unchanged.

Hmm...

[MeatyPulp]

I thought about this too but unarmed strikes are always considered light weapons so you can't use Impact on them...

[Quintain]

You can't apply the Impact special ability to unarmed strikes, as unarmed strikes are always considered to be light weapons.

I believe that if you use feral combat training to use a natural weapon to inflict the damage in question it will work, but stimple unarmed strikes (improved or otherwise) cannot by RAW.

[Quintessentially Me]

CRB indicates unarmed strike is always considered a light weapon. IUS doesn't appear to change that. Impact only works on non-light weapons, so I would rule that it would not apply for that reason.

If it did, I would further rule it doesn't stack with Strong Jaw as it appears to be a similar enchantment type, even though one affects manufactured and one affects natural weapons.

[Quintain]

Quintessentially has it right..it won't stack due to Impact being an magical size bonus of 1, and strong jaw being a magical size bonus of 2. Same bonus types don't stack.

[Kazumetsa Raijin]

Awesome. Thanks guys :D

[Nefreet]

Might be a decent idea for an Animal Companion, or a Wildshaping Druid. Still $16k, though.

[James Risner]

Nefreet wrote:

Might be a decent idea for an Animal Companion, or a Wildshaping Druid. Still $16k, though.

Natural Weapons are also always light, so Impact is a no-op on an AoMF.

[Nefreet]

Not always. You can Power Attack with natural weapons, and you don't suffer the -50% damage that Power Attack specifies for off-hand or light weapons.

[James Risner]

Nefreet wrote:

Not always. You can Power Attack with natural weapons

I couldn't quickly find it, but I thought there was a reference that they were light but you gain normal power attack with them?

[Kazaan]

Power Attack doesn't care if your weapon is light. It only cares if it's used as an off-hand attack or a secondary natural attack. Normal iterative attacks/main-hand attacks, even with a light weapon, deal full Power Attack bonus damage. Same with Primary Natural Attacks.

[Cap. Darling]

If impair can only be put on melee weapons and AoMF can only be enchaced with stuff that also works with unarmed attacks, i think no.
But the next question is why would you? Isent it better to get +5 on the amulet?

[Kazaan]

At lvl 20, the difference between a medium Monk unarmed strike and a Large is an average of 7 damage, whereas the difference between the +2 bonus value of Impact vs just taking +2 to the enhancement bonus is worth +2 to both attack and damage. Since Monks need attack more than damage, I'd say the +2 to enhancement bonus is superior. at least up until lvl 16 where the increase to damage would represent more than +4 average damage increase between medium and large size. And it doesn't change the fact that it doesn't apply to light weapons. Better to put it on a Temple Sword.