I'm making a very small (VERY small) mod. All it is is an edited gatling gun. Extremely overpowered at that. Why? Because I want it to weigh little to nothing so the actor will still go as fast as if they were holding nothing, AND make it have infinite ammo. How would I do this by editing the .ini?

Well, assuming you have the ini (Coalition.rte\Devices\Weapons\Machineguns\GatlingGun.ini) you need to scroll down until you see

and then continue scrolling down until

Change RoundCount = 100 to RoundCount = -1.
Make sure you don't mess up the capitalization or tabbing, as it will break if they are not correct.

Next, scroll down a little way to

Look just below that for

Try changing that to a low value, like 1.
Save the file and run Cortex Command. If you've not broken anything, it should load without problems.

Feel free to experiment and change other values, and observe the effects it has.
Everything you need to know about modding in CC is a handy compilation of useful threads, should you wish to experiment further.