PW7 is a meaningless value if you do not know where your IHS is set.
Your gun on PW7 with the IHS backed out to 6mm is a whole different critter than with the IHS screwed all the way in.
The 125 bar in conjunction with a weak hammer spring adjustment can actually reduce velocity because the plenum pressure is over powering the hammer and shutting the valve faster and reducing the amount of air getting past the valve.
Pressure alone is not enough. The valve needs to remain open long enough to provide sufficient air volume to accelerate the pellet or slug until just before it exits the muzzle.
Try setting your first reg @ 150 bar, the 2nd @ 90 bar. That should leave plenty of room to increase the pressure at the second reg. Adjust the IHS until it is 6mm out from the top of the hammer spring cap.
Start shooting and measuring velocity. Very slowly open the 2nd reg. Shoot the gun and measure velocity with each adjustment. I shoot 10-12 shots with each adjustment. Keep backing out the 2nd reg until you are 10-12% over your target speed. Then start adjusting the IHS in about 1/8 turn or less at a time. Test for speed until you reach your desired velocity. From there you can tweak the IHS in very small increments in and out until you have consistent velocities.
Don‘t try adjusting the hammer spring and reg at the same time. One adjustment at a time. Reg first to establish velocity and then hammer spring 2nd to achieve balance between the hammer and plenum pressure.
Hope this helps. If anyone has better advice please share. The OP and I would both be learning.
ALL:
Sorry, I guess I wasn't very clear on this. I have been shooting 15.89 FX .22 pellets(sometimes JSB 15.89 pellets but got better groups with FX.) since I got the gun. It has always shot at 885-ish FPS(std deviation from 3 to 5), with IHS at 3turns from all the way "closed" to the right. Power wheel at 7 and First reg at 105, 2nd at 75. Was getting 100-125 shots per fill on the 300cc tank(250 Bar to about 150 Bar). My goals were to maximize shot count, great accuracy and a settled shooting experience. I have been tickled with the gun!
Last week I started getting the "odd" pellet or 2 in a magazine shooting 30-35 FPS slower than the AVG speed, screwing up the std deviation. I cleaned the barrel, etc. but did nothing else to the gun. I have not dropped the gun or mishandled in any way(at least to my knowledge).
Yesterday, I started getting significantly slower speeds(changing nothing)and still wider variations(ie.750's and 30-40 FPS swings from that AVG. Doesn't make sense to me......so I started to up the 1st reg and 2nd reg pressures(PW at 7) to 150-ish and 125. Still slow speeds. So, then I started to play with the "adjust" IHS, moving up and down to see what was happening or how results were varying. I am baffled as to what is happening and why such a change. Oh, and all the shots were going left 4 inches at 25 yards. Made no sense to me. So, slower speeds and shooting left, why?
I've gone back to re-setting the original pressure to 105(1st) and 75(2nd), PW 7 and IHS at 3 left from far right(clockwise). Still getting 750 -ish FPS.
Hope this explains things better. It is either reg issues or HS. Nothing else that I know of to adjust on this Maverick.
Pat
