Hmm, the Massive Ammo option seems to cause a GPF at apparently random places in the map. So far, it would appear to be around the first bandit base after you get to the Doc. Everything else is fine. And no, I'm not using the RELOADED crack.
I was actually doing that. Unfortunately, it really is hit-and-miss if it's going to crash the game when you enable it to top-up one's ammo - and without any kind of manual save system, it can become a minor irritant.
Edit: Ah, it helps to realise that enabling the Mass Ammo option only fills the reserve for your currently equipped weapon. Filling everything up at a save-point, then going on a sorté seems to be the way to go.
Damn, this just ain't happening. Unfortunately, if you leave the Mass Ammo option disabled, the game has a nasty habit of resetting your ammo count whenever something "interesting" happens.
Just add loads of cash and buy ammo upgrades and all the ammo you can get your hands on. That way you'll hardly ever run out of ammo.
--------------------------------------------------------------------------- "(Laugh) I never met my brother, until the day he killed me. (Sigh) We are a... complicated family. Wouldn't you agree?" - Paxton Fettel