Does this design get better performance?

Max performance means I don't have to rush out as far to get within firing distance. The barrel is so short that if I switched them it would probably fire worse than it does now.

Part of the reason for the in line design is because I use these cannons while airsofting as a rpg (It's a 2in barrel firing nerf pocket footballs). I suppose I'll just bite the bullet and make a 3 foot barrel and just chop a foot of the gas chamber. When I get some more cash together I'll go buy ...

I recently made a simple sprinkler valve cannon (4 foot 2in pvc pipe gas chamber to a blowgun modified sprinkler valve). I've done tests at around 100 psi and I've getting around maybe 100-150 feet. I've seen similar guns at half that pressure go 200 feet. I think it might be my barrel length ...

I was messing around with some figures in spudfiles and the barrel effect length is confusing me. It seems that having a really long barrel is more effective. anyone know what the best barrel length is for a 1" pneumatically actuated sprinkler valve cannon?