There is no such thing as accuracy
As anyone who has ever seen me play can attest. Long rant ahead.
Actually, it isn't accuracy. We are shooting poorly made water balloons if you think about it - what person in their right mind would snipe with a spitball with the aerodynamic qualities of a Volkswagen? Other than Salm?
What we seek is consistency, not accuracy. We want to create conditions that cause our paintballs to all hit at the same distance as close together (grouping) as possible. Those conditions depend on the paintballs being identical (spherically and in blemishes), the paintballs fitting the barrel in the same way and the air that reaches that paintball hitting it with the same force in the same place each time.
After it leaves the marker, we have humidity, temperature, wind and (for uphill shots) gravity to contend with. Stability of shooting platform and speed of compensation of aim of the followup shot are the only thing we can affect once we're on the field.
Each paintball leaves the muzzle at + / - 10 fps of the previous one everything else being equal. Doesn't matter if it's coming from a tube the short length of my Johnson or an eighteen inch sword, it still is adjusted such that it leaves the muzzle at 295 (or whatever) fps. It's going roughly the same distance every time.
How much it's exit characteristics (spin, yaw, turbulence, shape) match it's predecessor's out the muzzle, and how much the conditions it meets (wind etc) stayed the same determine how closely it'll hit to its predecessor.
The proof is simple to provide - accuracy by volume is the standard. One shot one kill is for whenever I'm supposed to avoid shooting a team mate crossing my shooting lane.
Exhaling,
Larry Janecka