Air Arms Owners Club

I'd be interested to hear other's thoughts on the optimum reg pressure.

I've just dropped the Altaros regulator set point on my S510 to 120bar according to the std AA manometer. Now I'm getting very consistent velocity as it comes off reg, so consistent it's not possible to see any change from 125 to 100bar. So overall, from 190bar to 100bar I'm seeing a slight drop from 776 to 772fps (8.44 gr) with rarely more than +/- 1fps over 10 consecutive shots. The only surprise is the tail off is steeper than expected so I get from 772fps to 760fps in 5 shots. It's almost as if the reg is set at 100bar and too low, but that's not what the gauge is telling me.

Previously I've had the reg pressure at 140 bar (where it had crept of its own accord) and 125bar. 140 was much too high so was getting 772-770fps then a spike to 780. 125 was giving 775-772 with a slight increase to 778. So I think I've got it about right. Now I need to check shot count over a few fills.

Hi Tony, I wouldn't put to much faith in the A/A gauge, notorious for inaccuracies

Yes Roger, the old type with the conventional dial and pointer gives a much more precise relative indicator even though the indicated values may still be inaccurate.

I think I'm seeing some temperature effect because I was expecting the velocity to level out at the previous peak (780fps) when I lowered the set point from 140bar. Possibly the optimum is just above 125bar, 130 maybe. Anyway, I'm happy with the 776-772 range and I'll probably leave it at that.

Edit/Update:
Definitely a temperature effect. I ran a full string in the warm today, 60 shots 776-780fps plus three shots at 781,782,782 around the 120bar which I took to be coming off reg. In total, 69 shots were above 770fps, 75 shots above 760. I'm happy with that.