In which order do multiple changed to damage type occur?

[karossii]

The specific thing I am interested in is a shield.
Shield Spikes say;

"These spikes turn a shield into a martial piercing weapon and increase the damage dealt by a shield bash as if the shield were designed for a creature one size category larger than you (see “spiked shields” on Table: Weapons). You can't put spikes on a buckler or a tower shield. Otherwise, attacking with a spiked shield is like making a shield bash attack.

An enhancement bonus on a spiked shield does not improve the effectiveness of a shield bash made with it, but a spiked shield can be made into a magic weapon in its own right. "

The bashing enchantment says;

"A shield with this special ability is designed to perform a shield bash. A bashing shield deals damage as if it were a bashing weapon of two size categories larger (a Medium light shield thus deals 1d6 points of damage and a Medium heavy shield deals 1d8 points of damage). The shield acts as a +1 weapon when used to bash. Only light and heavy shields can have this ability."

So... changing it to a martial piercing weapon then changing it to a bashing weapon - is it now dealing piercing or bludgeoning damage?

[IcedMik]

This is interesting. Both rules are exceptions to the rule that shields aren't weapons, so I don't know which one would overlap, if you're even allowed to place the bashing enchantment on a spiked shield.

It also should note that Bashing doesn't specify bludgeoning damage, but rather "bashing" weapon, which I don't see coming up anywhere else.

Reality, it would still be piercing. As a DM, since P/S/B damage doesn't come up too often, I'd say that a bashing spiked shield would be both B and P.

[Gauss]

My understanding is that a bashing shield effect is something you cannot combine with shield spikes. So, you either get the bashing shield effect of the spike effect but not both at the same time.

- Gauss