30 rounds in a mag is actually quite a lot for TTAC3. The arena is pretty small so you don't usually get into annoying standoffs where shooters just keep trying to pick away at each other. Action tends to be pretty fast and a skirmish is often resolved in minutes if one side manages to put together a cohesive rush. Even with cover fire, it's actually hard to run out two standard mags.
Want nearly free GBB gas?