Little variations surely do make big differences

. . . in reg and/or hammer spring settings.

Playing around with another one of my toys. It's amazing how the slightest little changes can make a big difference. Readers digest - I had an initial tune set on this gun shooting 36.2g ( .25 cal ) slugs at around 906fps. They were pretty good at 100 yards but I thought could have been better / a tighter group. I figured if I adjusted the power a little to send them 915 - 920fps that might tighten them up.

____ NEGATIVE ____

Instead the grouping (at pretty much all ranges - 40, 70, 100 yds) opened up and got worse. I backed it back down and now have it settled at around 908fps. Not to shabby considering there is a little bit of a breeze going on now - good thing about the wind was that it was mostly steady. Operative word in that last sentence - "mostly". 

Marked - shots #1 and #10. #1 was basically the sighter - ok - wind is pulling a bit to the right - I'll just compensate and hold off to the left. Guess what got turned off / stopped at shot #10? {sigh} lol

rti_prophet_100yds_nsa_36.2s_3rd_try_after_speed_adjust.1601220238.jpg

 
JD i was thinking the same thing at the range last week. Brand new to airguns here. I took shots at 25 yards and they hit about 6 inches low. I turned the hammer spring a half turn and took another shot, it was a little high. Turning the tension up a half turn brought the POI up 6 inches, no other changes. Crazy.

It seems this is a very finicky sport and I'm not sure how guys are getting results. Pellet size, weight, reg pressure (never mind creep), hammer tension. Seems you can fart and the next shot is off. My gun is zeroed for 25 yards but if anything slightly changes I'd have to start over and re zero again. Is that the fun in it all? Constant fiddling? Every first shot on a new magazine is off because regulator pressures seem to change as the gun sits. Its a bit baffling.
 
@mr_spock -- it's just not logical is it? ( sorry - couldn't resist . . . lol )

Ummmm ... if memory serves - you too recently purchased an RTI Prophet? " Every first shot on a new magazine is off because regulator pressures seem to change as the gun sits. " - I believe as mentioned recently, this is, unfortunately, a known "bug" with the RTI reg. Hopefully they'll address it / come up with a solution and replace existing customers regs or at least offer up a good one for a reasonable price point. I just dry fire a shot after each fill and watch the reg gauge settle to where its supposed to be. Ideal? - No. Waste of air - yeah. {sigh} Better than wasting a shot though.

As to your gun apparently "changing all the time" (?) - it certainly shouldn't be doing that. Find an ammo that it likes, figure out a reg and hammer spring setting, get it zeroe'd at ( in your case - 25yds ) and then just go from there. If 25 is you're zero then you'll have to figure out your hold over / hold unders and/or get an app like strelok pro and mark up the elevation turret on your scope so that you'll know how much to dial it up/down for a target at a given range.

Twiddling with them ( the guns ) is part of the hobby (I believe) for a lot of the guys in here - myself included to a degree. I've got four now - three of which I no longer fiddle with - it can take a while and some hair pulling (lol) to find and settle on a good tune. My .22 Taipan Long shoots lights out ( like laser accurate ) with it's current setup - I'm currently shooting 23g H&N slugs out of it and it's crazy accurate and I still get a decent shot count out of it as those slugs are on the light side (for slugs) but they still pack a punch on woodchucks and other critters - out to and beyond 100 yards. All I do with that one now-a-days is feed it air and ammo, and periodically clean the barrel. I ain't dinkin' with it! :)

The fourth gun that I recently purchased is my RTI and I'm about done dinking with it now (finally) as I ~think~ I've found a pretty decent tune with it and the NSA 36.2's.

Good luck!