Andrew, the reason that paintball is going to compressed air at 3500 - 5000 psi is because first, its a consistant shot pattern ( no pressure drop due to cooling gas ) second, quicker recycle or shots ( my electronic marker thats not all that quick fires an accurate 28 balls per second. Co2 cant cycle that quick without makor pressure drop problems ) and thirdly, with one charge I can nearly fight all day passing over 3000 rounds through my marker and whats more, I will still have some air left so that I can clean and test the marker at home and lastly, air is easier to refill that Co2. Its litelally plug and play. Plug it into the air source and watch the pressure gauge.

earlier air bottles were 3500 psi. We now use either 4500 or 5000 psi bottles now.

I hope this explains it for you.

One note, in the early days of Robotwars pneumatics a few people did indeed try compressed air. Paul Cooper from M2 and Technobots for one. But they switched to Co2 due to the higher amount of stored shots. A steel or Ally air bottle would be huge, weighty and very fulnerable. I have a diving bottle at home filled to 5000psi air. I use this to refill at home. This bottle is very heavy.

Regards.

Mike