The Real Value of Low Pressure
Low Pressure = working regulator = consistency = convenience Is converting to Low Pressure worth it? The quick answer is: If you are a Co2 user, play in a variety of temperatures and you can afford it - yes. I personally own a number of guns which I have converted to “lower than normal” operating pressure, and I’m happy with every one of them. Although there are a lot of people who will tell you it’s just a gimmick, to me, they’re just looking for the wrong results. To this point I have seen no definitive proof that LP guns shoot better, farther, or more accurately. If that’s what you are expecting, there’s a good chance you will be disappointed. However, there are several real advantages, especially for Co2 users.
Aside from the sound level and cold weather usability detailed on the Blow-back LP FAQ, one of the single biggest advantages to operating at lower pressure is it actually allows you to put a regulator to work, giving more consistent velocities.
On a normal pressure gun -- meaning those designed to operate at normal Co2 tank pressures of 750+ psi – a regulator has anywhere from “a little” to “less than zero” effect. For example, a base Spyder can be sprung to operate with a fair amount of reliability at 700 psi or so. On a hot day with a Co2 tank putting out 900 psi, the regulator is only reducing the tank output by 200 psi (and not for long as pressure drops with use). On a moderate temperature day, when the Co2 tank output pressure is about 750 psi, the regulator is barely working. On a cold day, when the tank output is less than 700 psi, the regulator has to be run wide open and becomes nothing more than an expensive gas-thru grip.
On the other hand, consider the above numbers if the gun is operating at 400 psi. In all three situations, the regulator is working, reducing the tank output pressure by a substantial amount. In my experience, the more a regulator regulates, the better it works, and the better it works, the more consistent the velocity.
Aside from the fact that consistent velocity is a key performance factor when it comes to maintaining consistent accuracy and range, there is also another byproduct to consistency in the form of long-term convenience. With a good regulator like the Palmer Stabalizer for example, there is a 70:1 input/output ratio. That means it takes a movement of 70 psi going from the tank into the regulator to change the regulator output by 1 psi. Even if the tank pressure drops 300 psi, that still equates to less than a 3.5 psi change in what’s actually going into the gun. And 3.5 psi isn’t enough to have a noticeable impact.
How does that kind of consistency manifest itself in the real world? To put it plain and simple, outside of varying limits at fields, I never have adjust my velocity. Never. Consider this: over the 6 months leading up to the writing of this page, every month I have used my Low Pressure Model 98 on Co2 in temperatures ranging from the lower 40's to the 90's. I have adjusted the velocity one weekend - in January - when I had to lower it below 250 fps for night play. I set the gun in the mid 260's the next day and that is right where it has remained ever since. I haven’t so much as put a tool to it. I don’t even carry an adjusting tool to the chrono station. Despite playing in 50 degrees of temperature variations for the last 6 months, each day I have been able to walk up to the chrono, fire a few shots at about 265 or 266, and go play (that particular velocity range may seem low but is where I get the best results from the Flatline barrel).
As other people on my team can attest, that kind of consistency is unfortunately not an attribute of a stock Model 98. It is also not a fluke connected with my particular gun. I have two other LP guns, one I have been running for about 2 years and the other for a year and a half, which are the same way. As long as I leave them alone, I never have to adjust the velocity regardless of the temperature changes I see. To reiterate what I said above, If you are a Co2 user, play in a variety of temperatures and you can afford it - yes, converting to Low Pressure is worth it - if for nothing else, just for the convenience.

-Billy Goodman