I play the same way. I almost never finish a game. I just setup a defensive line near my starting point and defend it. So I need alot of ammo. What I do is use the Editor to give my Tanks, AT guns...etc, all the rounds they can hold,
Then after doing this,
http://forum.1cpublishing.eu/showthread.php?t=11566
I go into my savedgame file and tweak the weapons,
I've been doing this for a long time(tweaking the savedgame files) so it doesn't take me long. Doing it for the first time will take a while and it only effects that saved game.