When working with Air America regs, please remember that the adjustment nut on the bottom of the reg can be screwed in to the point of bending the pin, causing the reg to creep on you.

If it is the first time using the reg on a new marker, you can unscrew the regs adjustment nut all the way if you want to, and the air will still be sealed even without a piston spring or nut in place. (if you want to test your reg, you can put it on a marker, gas it up, remove those parts, and fill with water to see if any air bubbles out, if it does, your reg is creeping and needs a new seat and pin). slowly screw the nut in until you have enough pressure.

You should NEVER screw the adjustment nut in when it is not aired up.

Tip for Vigilanti: MAXIMUM pressure output on a stock Vigilanti (with both spring washers) will have 6 threads still showing of the adjustment nut.

Tip for all AA regs : the seats are Crushed when they are assembled forming a perfect seal. If you've taken a reg apart, you'll notice the seat has a raised ridge around the outside diameter, this is caused by the seat conforming to the regulator, the are not manufactured that way. This is the reason why the seats cannot be flipped or re-used. Once you split the gas body and the piston housing (two halves of the reg), the seat must be replaced to avoid creeping. so if you don't need to open the reg, don't. never try to clean that part of the regulator, you'll just make things worse.
Another important thing to remember is that the seats are directional, while you may not notice looking at the seat, the entire seat is tapered, with only one side "snapping" into the Piston housing when new, if you put the pin onto the piston housing (the opposite side to the pin) it should not move around, if it does flip it.

Below, you see a new original Air America seat next to a USED Air America seat on the right, notice that it looks as though the reg was formed with the ridges, however those are created when assembling the regulator and help it to form a perfect seal. Because of this, the seat can never be reused, even on the same regulator.

Gen 1 Vs Gen 2 seats: A very little known fact is the two different generations of seats. There is no performance difference between the two, but they do have a small impact on first use. Below you will see the two seats, same dimensions, and same material, however the one on the left is "pre-broken in" which means it will stay where you set it on the first use. The one on the right is not broken in, which means after 5 or 6 cycles (shoot 5 or 6 balls) you will want to recheck the output and velocity, it may go up from where originally set. Once used a few times, it too will stay consistent.

There is NO output gauge port on any air america inline regulator. there are two input ports and a burst disc. Please note the burst disc is NOT the same threading as a unified burst disc (burst disc/nut all in one), using these will strip the ports.
Some regulators have a second safety built into them. It is built into the piston as seen below. the left piston has a blow off valve built in that will bleed out air if the regulator over pressurizes, before the burst disc blows. On these regs, it is in fact safe to remove the safety, and use a plug. Gauges however have a different threading and still CANNOT be used with the regulator.

If you have any questions on any AA regs, please let me know.