thus if you INCREASE the distance over which to lower the ball, you lower the pressure... meaning AT lower pressures, you would in theory want a longer back than at higher pressures. This is what i was trying to get acrsoss, but i was half asleep and admit it didnt make much sense1. Air pressure behind the ball is what causes this acceleration to happen. This pressure varies between the different guns but is generally between 50 to 125 pounds per square inch at its peak. The air pressure peaks right when the ball starts moving down the barrel, after that, the ball moving down the barrel creates a bigger chamber so the pressure drops. This is why low pressure guns are a myth, in reality all guns shoot at considerably lower pressure than 200 psi.
If you reduce the distance over which the air has chance to accelerate the ball, you will require higher pressure, so reducing efficiency and increasing the risk of ball breakages
I've deffo got a vid somewhere of Tom Kaye putting his tongue in teh breech, it was a no-rise x-mag with a lvl 10 kit, blue i beleive. But thtats besides the point...[2. http://www.automags.org/resource/tech/tomstech/03_spinning.shtml
It's not really Aerodynamics as such, as in Aircraft or car drag coefficients. Though clearly, a balls aerodynamics is a factor.
When you are talking about projectiles, like paintballs and bullets its Ballistics, trajectories and Ballistic Coefficient's etc. I know a bit about Ballistics
The Ballistic Coefficient of any projectile, is a representation of it's aerodynamics, weight and shape...sort of.
I think it was John Sosta who put his tongue in the breech of an LX!
Bullet ballistics dont work for paintball, due to the fact a paintball has a liquid inside it. If you've ever lobbed a water balloon and watched it woble in mid air, thats the kind of thing a paintball is doing. Thus the field of pure ballistics doesnt really apply to painballs, because while they have weight and aerodynamic factors, the make up of the paintball is so radically different from anything ballistics usually deals with, it'd be hard to compare.
A point i made ages ago was that artillery shells do not have a solid inside, rather a semi-fluid powder (dont get me into the fluid properties of powders), making them similar, however the shell being so much heavier than the internals kind of wrote any impact that made off. A paintball however has most of its weight made up by the fluid, thus would in fact be closer to a water balloon.
I might see if I can get hold of a high fps camera and fire some paintball when i'm back at uni, would be really interesting. Especially if i could find some paint where the outside is transparent enough to see the fill.