(adsbygoogle = window.adsbygoogle || []).push({}); The codes I am using now, changes the ammo to like 1023 bullets "clip size"...and it stays at 1023 for a few rounds. But then it will just start dropping. So its sort of like unlimited ammo, but just doesn't last very long. Is there a code that works for private match or even online that will give truly unlimited ammo? How about player_sustainammo 1...will that work?

That's the right dvar but "player_sustainammo 1" is cheat protected. So it won't work.
My advice is bind "give ammo" to a button, so when you start to get low on ammo, you can press the button and it will replenish.

Yea I have that already, but the main thing is when I play with people they run out of ammo. I had a friend have the ray gun last til round 50 of ammo, then it started running out. I have no clue why it does that. Have been trying to figure out a way to make it work longer

Maybe you can try this one: sf_use_ignoreammo 1, i don't know if it work.

Moreover even if player_sustainammo is cheat protected sv_cheats is set to 1 in zombie, so i don't think this is in issue. Maybe player_sustainammo is readonly ?
You should try both, i don't know if they work.