I was told that at the save points with the item boxes you could do a glitch with the grenade launcher where you get 250 grenades in your inventory, if this is true then how do you do it?
Yes it is possible to do this with all types of grenade rounds, including acid rounds, and incendiary rounds. You need the grenade launcher and 2 different types of ammo(not including whats already loaded in the launcher). Here are the steps in which to do so, using the incendiary rounds.
1.Put all your items in the item box
2.Put your grenade launcher in the upper left slot of your inventory
3.Put incendiary rounds in the upper right hand side of your inventory
Helpful yeah, but it's sort of hard to actually accomplish because even after reading the exact way to spawn grenade rounds you pretty much have to run into a stroke of sheer luck. You also end up gettting alot of rounds for the ammo that you don't exactly want lol. It's only slightly difficult because it's a glitch and not a cheat code so the game doesn't always recognize it. If the above strategy doesn't work for you, follow it to step 8 and then try different things and ideas you'll eventually get it.