FX Impact M3 Tuning Advice (inconsistency)

So I have my Impact shooting pretty decent groups after tuning but most of my shot charts look like this. I am shooting 18.1g FX ammo at 120/85 bar and usually shoot between 880-900 fps.

I did notice my regs creep a little and that’s why the first shot is low, but why the buildup like that. Should I have more pressure at the rear reg so it has a stronger contact with the valve adjuster? I can’t figure out why my strings are like this. Anything I can fix?


IMG_9915.png


IMG_9914.png
 
Here ya go:

 
It’s a 500mm
I was going to say low, I think he's having to open the valve too long to get the velocity. For Giggles I'd go up another 10 bar or so and start reducing his hammer/dwell. I'd also increase #1 to 140 faster refill. We don't see hit shot timing and with low pressure that'll play havoc with speeds...JMHO
 
So I have my Impact shooting pretty decent groups after tuning but most of my shot charts look like this. I am shooting 18.1g FX ammo at 120/85 bar and usually shoot between 880-900 fps.

I did notice my regs creep a little and that’s why the first shot is low, but why the buildup like that. Should I have more pressure at the rear reg so it has a stronger contact with the valve adjuster? I can’t figure out why my strings are like this. Anything I can fix?


View attachment 514956

View attachment 514957
I can accept that 20+ FPS spread for a regulated airgun which cost s$300.
For an airgun that cost $2000+ not so much.

A $2000+ airgun better be almost perfect.
As in I can shoot it without tuning it.