How viable is shrink item and massive projectiles?

Question

I'm sure it's been done many times in many variations over the spell's history, but I'm having trouble finding any reasonably conclusive ruling or argument as to whether or not it should work. Is it possible to use shrink item on a large, dense object, then fire the tiny version of it and un-shrink the projectile mid-flight?

The first obvious method is to activate the spell's command word before it strikes its target, thereby upsizing it and retaining its momentum. A command word is generally a standard action, so this clearly won't work in close-range scenarios, but would it be possible at long range where the projectile conceivably took more than one round to reach its target? Does the item have to be at hand for the command word to work? If not, what's the range of the command word?

The second method would be to simply allow the shrunken item to resize automatically after striking its target. Would it retain any momentum as it increased in size? Would the expansion be fast enough to deal damage on its own?

Answer 1

This combination would not be any more viable then a regular sized projectile

From the text on Shrink Item

Objects changed by a shrink item spell can be returned to normal composition and size merely by tossing them onto any solid surface or by a word of command from the original caster.

This shows that the item will only resize on a command word or by tossing the item onto a solid surface.

If you compare this to the wording of Reduce Person

Melee and projectile weapons deal less damage. Other magical properties are not affected by this spell. Any reduced item that leaves the reduced creature's possession (including a projectile or thrown weapon) instantly returns to its normal size. This means that thrown weapons deal their normal damage (projectiles deal damage based on the size of the weapon that fired them).

This shows 2 things. First, that any resizing while being fired would be specifically stated in the spell. Secondly, regardless of item size, the damage is based on the weapon which fires it.

Answer 2

Projectile weapons won't work like this RAW, thrown weapons might depending on how your DM handles the unshrinking on impacting a solid surface i.e. your target. It's noteworthy though, that while the command word can only be used by the caster, that caster need not be the thrower and might have readied an action before someone, like a monkey familiar with the Throw Anything feat for instance, threw something that might not be a "conventional" weapon. On a related note, it may be better not to bring up this specific spell when trying to convince your DM that it would be really cool if your raven familiar could deliver command words for you.