FX regulator change

[StarlingChaser]

I have a quick question. I’ve never had this happen or maybe just not caught it. I did a lot of tuning on my .22 FX Impact this winter and got it shooting H&N 27 and 30 grain slugs butter than I had ever dreamed I would. Most of this was in the 30’s to low 40,s. My reg was set at 154 bar and I have the really nice Wikea gauges. Since I am off work I have been doing pest bird control (alone ). Anyway last few days I have been missing a lot of shots so time to re-zero. Zero was off but so was the consistency. I looked at my bar setting and it was 145 instead of 154ish. I hooked my magneto speed chrony up and the shots were from 935 up to 976 and everywhere in between. 1st I was going to creep the reg up slowly, shoot, creep again till I got 154. After my 1st reg adjustment I was still lower but my spread was back to 3-4 FPS. Every adjustment after that was the same spread like it used to be. Long winded I know but my question is, was this due to the temp difference which was now 75 by the way or should the reg be moved once in a while just to keep everything loose for a lack of a better way to say it. The change in bar kinda makes sense maybe but not sure. Never left everything the same this long before. This is still the older style reg but always did perfect for me. The gun never sits very long between uses either, at least once a week. 

 

[biohazardman]

Since it was new my Impact used to jump up and down 20bar on the reg every few hundred shots. This equated to several inches of drop or elevation at 100 yards. At first I just adjusted my scope that is until I figured out it was the reg. I then ordered a Huma reg. On removal of the original FX reg I found this flat spot on piston rod. (right in the pic) Probly was the problem. Was a real hassle getting one from FX, hence the reason for the Huma. It took several months and then, no excuse for it but , they sent me this regulator rod, (left in the pic) it was worse than the original! Grrr. But after all is said and done they sent me another that was good. From what I have read it seems that the rod may be damaged/worn by the washers if they have burrs or are sharp on the inside which makes sense to me.

 

[Swish]

I had the same issue in the beginning. Almost every time I'd adjust the reg it acted like it would settle in after a shooting session and I'd have to re-adjust slightly to get the pressure back up. I assumed it was the same issue that Biohazardman had but it has stopped doing it. I'm not sure if I found a sweet spot or if it finally broke in.

I've often wondered how much the plastic piston expands and contracts at different temperatures and what effect it might have.