My A-5

I'm going to settle this right now because this arguement is making my
head hurt.

GTA, you have the irght idea in that the velocity adjuster on a tippmann
only creates turbulence, which is part of the problem with their air
efficiency (however i've always gotten excellent efficiency out of my 98).

On a two piece barrel, the back of the barrel seals the ball tightly in and
gives the pressure a chance to build up behind the ball without it being
able to escape anywhere else (aka around the ball). This gives you
propulsion.

The second half of the barrel is a (relatively) much larger bore size, and
therefore the ball is still guided yet not exposed to as much friction. This
doesn matter, however, as the air can new escape around the ball and out
of the porting. This quiets your shot, no more, no less. Length of barrel
only effects sound, astethetics, and utility (long barrels for pushing brush
or an air bunker out of the way, or short for maneuverability).

When you're talking about pressure, other outside forces dont come into
play that often. For example, it was a sort of myth in the paintball world
that atmospheric air pressure in front of the ball in a paintball gun caused
a slowdown of the ball. NOT TRUE. The guys at AGD set out to prove
that this was not true buy placing a lit candle flame in front of the barrel
of a paintball gun. They set a high speed camera to observe the
experiment. The candle flame did not blow out until the paintball had
passed through it and the 600psi or so wind blew it out, not the air in
front of the paintball.

NOTE: I know, however, why long barrels have such a stigma (yes, this is
from experience): every inch you add to a barrel, you are more and more
likely to break a ball in the barrel if something should disturb it or the
bore size is too small or it is a low quality barrel
*cough*32degrees*cough* and has imperfections that will result in a
goopy mess for you. His barrel is Smart Parts. Not an issue.