The rules on throwing objects through arrow slits

[Method Man]

Hey, so my friend is wanting to throw rocks through an arrow slit. He wants to get all the bonuses that improved cover will give him and I think he is also has concealment. This sounds very sketch but here is the situation:

He wants to make a 5ft x 5ft box made out of wood for 10 copper. He is a male human so he is medium size in this box. He is also going to make an arrow slit in the box for whatever size for throwing rocks of whatever size that will fit through the arrow slit.

Now I'm thinking there's obviously going to be penalties to doing this. I'm pretty sure there's a DC check for whatever size the arrow slit is when you attempt to throw a rock out. There might be vision penalties, attack roll penalties or even penalties for how far the rock can even travel.

I've tried looking this up but there's no specific situation that covers what's happening here so I'm going to the forums to get some insight.

And the build he is doing, by the way, is this:
http://paizo.com/threads/rzs2qkpe?I-Throw-a-Rock-at-it

[SlimGauge]

I can imagine something like a batting practice pitcher's screen.
Picture
Note, however, that you can SEE through the mesh so as to see what you're throwing at, something you can't do with the box, so you might need a different vision slit from the opening that your throw comes out of. And all you need for magic missile or other lines of effect is one square foot.

For 10 copper, that's going to be a relatively flimsy box. AM BARBARIAN will smash it in short order.

How about this ? Use the rules for a tower shield, except cut out the top right corner (or left if he's a lefty). When you set the shield on the edge of the square you're in, you don't get total cover but improved cover, but you can throw object at no penalty (because of the cut-out corner).

He'll still run into the problem that it takes a standard action to set up, so you'll have to let it stand on it's own once set.

It seems he really wants a Mantelet, but there really aren't rules for them.

[Chess Pwn]

Using cover rules you have no penalty for shooting out of an arrow slit.
Using perception/cover rules, you'd have limited line of sight and no mobility.
Using object rules, his little box shouldn't provide meaningful delay against melee attacks.
I'd say let him use it and surround him and laugh as he can't do anything as the enemies approach from behind him.

[Komoda]

Sounds like a pin cushion to me.

[Qalyar]

SlimGauge wrote:

It seems he really wants a Mantelet, but there really aren't rules for them.

The mantelet in that picture is pretty much a pavise with a mounting stand to make it easier to set in the ground. In Pathfinder terms, we'd call that a tower shield. Larger versions of the mantelet included big, boxy wooden things with wheels and arrow slits, which does indeed sound like what he's going for here. Under the D&D categorization of things, I think they'd have to be governed by the siege equipment rules, which are a hole with no bottom, honestly.

If you've set something like this up and are just trying to adjudicate the attacks, any side that is protected by an unbroken barrier provides full cover. Any side with arrow slits or the like provides cover or improved cover (following from the tower shield rules on marking edges of your squares).

If it's man-portable, then follow the spell targeting rules for tower shields. Otherwise, it's essentially a siege machine or portable barricade. Attacks that miss because of cover, or that are targeted against the barrier itself do their damage to the object per normal rules. Assuming this is just thin wood, that won't last long. Obviously, a mantelet made from metal plates or the like is a serious obstacle to attacks, and an even more serious problem to actually transport anywhere.

Penalty-wise, beyond the difficulties in transporting such a contraption, the character taking cover inside would fail sight-based perception checks made "through" solid walls, probably warrant a penalty for those made through arrow slits (especially if permitting improved cover), and would suffer the "through a closed door" penalties to other perception checks.

[Cevah]

You do get the cover and concealment bonuses against their attacks. I would rule, however, that they also get the same from yours. The reason an arrow slit works for arrows is because the tip of the arrow can be placed in the slit, and the rest of the arrow follows the tip when launched. When you throw something, your throw does not start at the slit, nor does it follow through like the arrow. A crossbow, slingshot, or gun would work.

/cevah