"Got you under pressure...!"

I’m commonly asked this question, usually by new owners of “nitrogen”, (HPA systems,) or users of regulators on C02 markers. Unfortunately, there is no quick and easy answer; the actual pressure setting depends strongly on all sorts of factors. What kind of gun is it? What regulator, or HPA system? What, if any, mods have been performed to the hammer/striker/valve assembly? What paint? What barrel? The list goes on. There is no formulae or equation for calculating the pressure, you have to experiment a bit to find the “sweet spot” for your particular valve and hammer combination.

Some background on terms:
First off, to reduce confusion, although I’ll probably add to it as well, here’s a quick run down of the terms I’ll be using: The “Supply” is the primary regulated air supply, either what comes out of a “nitrogen” / High Pressure Air (HPA) system, or after the regulator nearest the Co2 tank. A “Secondary” reg is whichever regulator is after the “supply” reg; In other words, the inline reg, such as a UniReg, Stabilizer or RG-1, OR, the marker’s internal reg in the cases of an Automag or Desert Fox. And of course, the “Internal” reg is the one built into the paintball gun itself, as in the Automag A.I.R. valve, but “internal reg” does NOT apply to “Pneumatics” regulators, such as the “Rock” or “Sledgehammer” on an Autococker. “Pneumatics” regs do not have anything to do with the velocity or the operating pressure of the marker. “Inline” regs refer to either the “secondary” reg, or whatever regulator is between the “Supply” and the “Internal” regs. As far as adjusting is concerned, “Up” means increasing the pressure, and “Down” means decreasing the pressure. Pay attention to how your particular regulator adjusts: On most regs, turning the adjusting nut or screw clockwise will increase the pressure, but occasionally, such as on an RG-1 or Equalizer, you turn the screw COUNTER clockwise to increase the pressure. And finally, the original PMS “Regulator” HPA systems had an oddball upside down and backwards thread to their adjuster: Turning it clockwise increases the pressure, but unscrews the adjuster from the body of the reg. If you pay attention to the direction, you won’t have any problems. Follow all this? Then here we go.

Markers with internal regulators:
Now, some ‘guns don’t need a particular setting; Factory-regulated markers like the Automag, Desert Fox or Equalizer, because they already have a regulator built-in, simply need an input pressure higher than the internal reg’s operating pressure. For example, an Automag uses approximately 400 to 450 psi to fire a paintball at 300 fps. The ‘rule of thumb’ is to have at least a 100 to 200 psi difference between each reg, so theoretically you’ll want to set the input to a ‘Mag to between 500 and 650 psi. However, AirGun Designs recommends between 700 and 900 psi input for best consistency and crisper action. The exact figure is irrelevant, as long as it’s sufficiently above the marker’s operating pressure.

Don’t have a gauge?
Don’t have a pressure gauge on the system that tells you what the input pressure is? No problem. For internally regulated ‘guns, like the aforementioned ‘Fox, ‘Mag or Equalizer: At the chronograph, with your goggles, with the gun not pressurized, and the HPA system or Co2 reg set pretty low, turn the gun’s velocity adjuster up almost all the way, as in almost completely maxed. You don’t have to lean on it, just turn it up gently, quite a ways past where it’s normally set. On a ‘Mag or ‘Fox, that’s “in” or clockwise. On the Equalizer, that’s “out” or counter clockwise. Now, with the ‘secondary’ reg turned pretty low, gas up the system. Fire a couple of shots, if you can, and note the velocity. Turn the ‘secondary’ reg (supply reg) up until the marker is shooting about 350 fps. You don’t have to have it exactly at 350, in that neighborhood is fine. Now, turn the gun’s adjuster down until you are shooting safely under 300 fps, and Bang, you’re done. Lock all the adjustments down, and go play.

Nonregulated markers:
Now, what about the unregulated markers? Like the ‘Cocker, Sovereign and Blazer? With a single-regulated system, whether HPA or Co2, here’s how: Set the marker’s velocity adjuster roughly halfway through it’s travel, again you don’t have to be exact, just in the ballpark. Set the supply pressure low, like 200 psi or so, just enough to operate the cocking mechanism, and gas it up. Now, again shooting over a chronograph (Goggles on?) fire three to five shots, and note the velocity. Turn up the pressure a tad, say 25 psi at a time, or 50 if you’re in a hurry. Fire a few more shots, and again, note the velocity. Repeat this, until you come to a point where the velocity does NOT rise with the increased pressure. It doesn’t matter what the actual velocity is, we’ll take care of that later. Now, once you’ve found this point, this is your particular marker’s “sweet spot”, or the pressure at which the valve and hammer combination work together the best. If you have the time and patience, you can fine tune the exact pressure, by slightly raising and lowering the pressure, to find the best “spot”. Now, lock down the regulator adjustment, if necessary, and fine tune the proper velocity by using the gun’s adjuster. If the overall velocity is pretty low, or terribly high, instead of cranking way down on the adjuster, or cutting springs, try installing a different spring, and go through the setting procedure again.

Now, again, you don’t need to have a gauge: Instead of turning the regulator up a particular amount of pressure, just turn it up a small fraction of a turn. On a UniReg, say a eighth-turn or so, on something sensitive like an RG-1, maybe a sixteenth turn or thereabouts.

Double regulating:
With a double-regulated system, again, like the internally regulated markers mentioned earlier, just set the supply reg somewhat higher than the ‘secondary’ reg. A good spec is keep the supply about 200 psi above the ‘secondary’ reg’s output. If the marker wants 300 psi, set the supply at 500, and so forth. Most Autocockers and Sovereigns can run less than 500 psi, with no mods, so set the supply reg to about 700. Many Typhoons, Strokers and Blazers need somewhat higher pressures, so you might want to set supply regs on these to perhaps 900. Once you have a decent supply pressure, then set the secondary reg as described above. If neither regulator has a gauge on the double-reg system, you can set the proper pressures much like the setting of a gaugeless system on a ‘Mag or ‘Fox; Set the ‘secondary’ reg high, adjust the ‘supply’ until you have high velocities, 350 fps or so, then readjust the ‘secondary’ to the proper pressure as before.

Blowbacks:
Blowback semi-automatics are more sensitive to proper pressures than pneumatically operated markers. This is because the hammer has to have a certain pressure/volume of air to properly ‘blow’ the hammer back to a cocked position. Some, such as the Tippmann Carbine, can actually run pretty low pressures and still shoot excellent velocities. Others, like the VM-68 or similar “heavy” blowbacks, need a fair amount of both volume and pressure to operate. With a single regulator, whether the HPA system’s reg or an inline Co2 reg, setting the proper pressure is easy. Again, crank down on the reg’s setting, maybe 350 psi for a lightweight blowback more for the larger, heavier ones. Open “choke” type velocity adjusters completely; these are the kind that use a screw or knob to partially block off the airflow. This type is found in Carbines, Pro-Lites, VM-68s and several others. For “spring adjusted” markers, set the adjuster roughly halfway through it’s travel. These are the adjusters that compress the spring that drives the hammer or striker; This type is found on Spyders, Mirages, Raptors and others. Some markers, such as the Indian Creek guns, have both; a choke and a spring adjuster. You can also add a spring adjuster to Carbines and Pro-Lites. For these, open the ‘choke’ adjuster all the way, and set the ‘spring’ adjuster about halfway. Now, gas it up, and fire it. You will need to be careful, as a too-low pressure will not cycle the gun properly; be prepared to “catch” it if it goes ‘full auto’ or burps. Turn the pressure up a bit at a time until the gun cycles reliably and consistently. Now, add paintballs, and fire it over a chronograph. Turn up the pressure until you get decent velocities, and the gun still cycles properly. Once you have just under 300 fps, you are done. Lock down the reg’s adjuster if necessary.

Pump paintguns:
Pumps can often use lower pressures than semi-autos, because less air is wasted in the form of “blowback” in the case of open-bolt semis, and the breech stays sealed longer for more efficient use of a fixed volume of air. Again, pumps are easy to set: Start with the adjuster roughly in the middle of it’s travel, and set the supply reg low. Simply fire over a chrono, and increase the pressure a little at a time until you reach your desired velocity. It’s as simple as that. However, many pumps, notably most Nelson-based inline valve pumps, are not terribly efficient at low pressures, due to the restriction of the very small-diameter “power tube”. Most of these will still need relatively high pressures for best performance, in the range of 500 to 700 psi.

Final notes:
On most of these setups mentioned here, once the pressure is set, use the gun’s internal velocity adjuster to fine tune the actual playing velocity from day-to-day. Regulated markers, especially with HPA systems, will give excellent consistency from game to game, and shot to shot, but occasionally you may have to fine tune the velocity because of different paint quality or type, or a different barrel. For the most part, the best all-around performance will come from using the gun’s adjuster, rather than changing the working pressure. Now, on all this, remember the cheap little gauges used in the majority of paintball gear are not terribly accurate.. As a matter of fact, they are commonly off by 10%, occasionally as much as 25%. Use the gauge as a guideline, not as a precision instrument. For that matter, don’t worry too much about precise readings: If the instructions say “500 psi” don’t worry if you end up with 453psi or 528psi, getting in the ballpark is fine. The important reading to go by is the velocity, if you get just under 300 fps, then whatever pressure you end up with is exactly perfect. Yes, it is possible to have three or more regulators on one paintball gun, but more than two are pointless, and usually will begin to restrict airflow. Some HPA systems, such as the Max Flow/Super Flow, and PMS’s MiniReg and 4500 systems, are more consistent in their output than other ‘single-stage’ systems or regulators, and so even double regulating is unnecessary, and only adds a possible source of air restriction.