KalNet Message Board

Reynolds number for a paintball at 280 fps is roughly 9.4 X 10^4.

To calculate the Reynolds number, multiply the velocity (280ft/s) by the diameter (0.057 ft), and divide the result by the kinematic viscocity of the air (1.69 x 10^-4 ft^2/s).
This is at standard atmospheric pressure and 80 deg F.

one would think that the more consistent the setup, the more accurate. the same mass, flying through the same air .... and if they were all imparted with the exact same energy, would land in the same place.

the issue is that the air turbulence created by the paintball as it flies screws up the flight path so much, that small inconsistencies in initial velocity tend to be masked by it. from our testing we have not noticed a problem with accuracy until you are up in the +/- 10 fps kind of range, which most gun/barrel setups should be able to provide you.

What Is The Best Way To Measure Accuracy?

Characterizing rifle performance using circular error probable measured via a flatbed scanner

The values are not fully comparable, because the all markers shoot in different temperature, humidity, with different paint and powerlets... But it is better to have some values than none, and along experiences, the most important thing is here still the marker - comonly when you have the best results, then you have the most efficient marker (partially because paintgun users commonly do no dry misrepresent thier measures or make them on Sahara sun or Asaska ice to have strange measures).

To be comparable with different velocity setiing, the measured velocity from the shoots has been calculated into the kinetic energy (Joules).
For quick comparsion 1 shoot on: 250 fps = 9 Joule, 265 fps = 10 Joule, 290 fps = ~12 Joule, 300 fps = ~13 Joule

The know best results are:

557 russc regged Halfblock Sniper - 9 shoots with velocity above 300 fps, 1 shoot 340 fps
488 WickedKlown2 GreyGhost 2008
472 Manning Duck (green/green spring combo)
471 PB Weasel Redux
470 drg mQ Sniper 9v Li-Ion - 1 shoot with velocity above 300 fps
469 3022 New Hammer w .683"
462 1996XJ Phantom VSC w. .679"
460 russc slamvalve unregged nelson - 18 shoots with velocity above 300 fps
453 drg mQ Sniper 9.6v NiMH
(442) Mootho Phatom w. .681" (4 no-reads, lower values near taken as reference)
439 greenmtnphantom Gargoyle
433 3022 PGP 6,85mm + 8g Ti hammer
421 3022 Sterling Bronze 10x7mm & 20g w .683"
414 3022 P68SC 7x14mm & 15g - 5 shoots above 300 fps
403 Mootho Microphantom w. .678"
393 oldironmudder old Sterling, regged, w .675"
390 splattttttt Gargoyle
365 turbowagonman Sterling STP w. .679"
353 3022 ZGP-94 7x12mm & 27g
345 oldironmudder old Sterling, unregged w. .675"
327 3022 P68SC 7x14mm & 15g (it is the same gun like with 414 J but with all shoots below 300 fps )


We an see that the best tunned markers can change energy in powerlet in 450-500 Joules kinetic energy "stored" in shoots. So with the todays best results idealy converted in stable velocity you should get between 45-50 shoots at 265 fps or 35-38 shoots on 300 fps.


For comparsion "out of the box" markers (untunned, or from profesional tunners):
483 Walker palmerized PGP mod. 1996 (3 shoots above 300 fps, velocity reduced after 9 shot)
447 RTP Viper (velocity adjusted after 6. shoot, 2 shoot no-reads, lower values near taken as reference)
(430+) toymachine palmerized PG (3 shoots above 300 fps)
(391) Carter Duck (total 38 shoots, 13 from them chrono no-reads, lower values near taken as reference, total 1 shoot was above 300 fps)
380 PPS Superstocker - 34 shoots between 235-300 fps
380 Phantom VSC - 37 shoots between 235-300 fps
270-300 PGP2 (depents on velocity setting)
(306) ZXS-200 - 55 shoots, but only 10 shoots, ∑80 Joules in 235-300 fps
287 PMI Piranha SB + Turbo Valve
230-273 Tiberius Tac-8 (semi-auto; depents on velocity setting)
242 TASO Vidicator I.
214 PGP (old-style valve)
212 ZGP-94 (depents on velocity setting)
212 Sydarm Gen. 2 (semi-auto)
160 Brass Eagle Tigershark
80 PGP "German" F-stamped (limited below 7,5J) - no shoots above 230 fps

First of all, I have a set of shots I'd like to share.


These were made with a stock 2k4 WGP gun, black magic reg, .684 Un1tec barrel, line SI lever changer in bottomline config, stock aluminum open face bolt. All shots were made without holding the pump, rubber band used as return spring. Shot interval was about 5-10 seconds as I only had two paintballs, so every shot I walked over and picked the ball back up after shooting it into a hanging bathrobe.

1. *forgot to chrono(
227 (adjusted)
296
300
304
289
291
296
297
10. 309
295
295
295
293
291
293
294
296
290
20. 294
302
291
292
294
296
299
298
295
296
30. 294
298
298
303
296
300
302
303
302
*lost ball*
291
40. 289
324
340 (WTF! Gun loses sweetspot, starts to shoot hot)
43. 291
233 - vented after shot

As you can see, not only does it get insane efficiency to rival the best Nelson setups out there, but the FPS curve is essentially flat until you get to the last 3-4 shots. I don't believe this gun was properly sweet spotted as you can see when the regged pressure dipped at the end the gun went all the way up to 340 fps. 43 shots in total, all of them in the top range of allowable velocities.

Keep in mind, this is an unmodified mid-pressure stock WGP gun with a 12gram changer in the bottomline duckbill.

So, there's a few things that are worth discussing here.

1. Regged low-med pressure 12 gram guns can get a flatter pressure curve, while getting just about as many shots.

2. "dead space" is less significant, if not inconsequential in a regged setup versus an unregged setup where all expansion is avoided.

3. The sweet spot on Snipers have potential for abuse. This is why I tell people who want to run unregged CO2 or HPA into their Snipers to get a pre-2k valve. Say you start at 280 fps, with the unregged pressure slamming your valve shut. Once your pressure starts dropping you will begin to have insanely high velocity as the gun is reaching its sweet spot the lower you go.

4. Why don't more stock class setups incorporate regulators, as a flat pressure curve is more desirable than a dipping pressure curve, given that you aren't losing many shots, if any.

I gotta disagree with ya a bit Alex on this one. Trigger SHAPE is preference, but trigger DESIGN is not.

There are certain characteristics, that make a well designed trigger very pleasant to pull, even though you may not like the actual shape.

Things such as -

* "extended inner raceway" ball bearings, so that the trigger doesn't rub on the inside of the trigger well. Look at a G6R Trigger, how frictionless that is compared to a shocker SFT/NXT trigger. Check out the pic below. The middle bearing has extended inner raceways, this way you can tighten the trigger down, and it still won't rub against the trigger well, dragging and slowing down the trigger

Posted Image

* Good adjustments on the post travel, pre travel, spring tension, activation point. Look at a Geo 2.1's trigger, how well it's designed versus a DM trigger. The DM's adjustments are terrible, the springs are ALWAYS too stiff, and the conical screws tend to wiggle inside of the threading, moving the points of adjustment. Also, the DM has no activation point screw, it's fixed



* Pivot point - the natural angle of the hand/knuckles is a 45 degree angle, and the plane is usually from the player's forehead through the trigger guard and pointed at the ground. Pivot points that are in front of the trigger (Evil Pimp) instead of BEHIND the trigger (Alias Intimidator) tend to be slower shooting guns, because your middle finger needs to travel much father to get the pull. You miss alot of pulls

* Trigger Edge - most people don't pull the trigger straight back, they press it from the side. Having a trigger that is rounded a little bit (Geo 3 / Ego 11) versus a trigger with sharp edges (Clone/Drone) feels alot more comfortable when pulling the trigger.


If a $450 Axe can have an amazing trigger, no reason any other gun that costs more shouldn't have it either. Triggers are EXTREMELY important in my opinion, if the gun has a shitty feeling trigger out of the box, everything just tends to go downhill from there.

Velocity has also yet to be mentioned. A 10% drop in velocity leads to a ~20% increase in efficiency.