Ammo pooling is done by setting up weapons (through the gunspec.txt file) to have their ammo bound to variables.
I think you should find the feature in the gunspec section of the manual. It's called something along the lines of "bindammotovar". Anyway, doing that will bind that weapon's ammo to a variable. With this comes a few nicities.
First off, you can now alter that variable at any time to change that weapon's ammo on the fly! The player doesn't even need to have the weapon equipped for this to work! You can also use the variable to check against with variable conditions.
Secondly, if you bind multiple weapons to the same variable, they are, in effect, sharing the same ammunition! This is called ammo pooling, but is not labeled as such. The ammo pooling is just an added benefit of binding multiple weapons to the same ammo variable.
I hope that cleared things up for you.
The one and only,
Only those who sow the seeds of their desires will reap their benefits later.
However, I have seeds of my own to tend to. I don't have time to be someone else's watering can.
