AirMaks Arms Katran velocity unstable?

[JimD]

If 945 is the peak velocity at the new regulator setting you may be fine. 95% would put you at about 900 fps which could be nice and accurate. If 945 is the 95% of the peak value you may be a little high as you indicate. But I'd shoot it before turning the regulator down.

There are "rules" we all use like 95% of peak but they don't work in all cases. If I set my P35-22 that low my first shot is way low on velocity. But it works fine on my Caiman. It's easy to say pellets are highly unlikely to work over 1000 fps but once you get under 950 fps or so it is probably best to see what your gun is telling you it likes.

 

[JaceSpace1369]

More information. The regulator in this rifle has no sticker nor identifying marks. I marked the factory setting and turned it 45* inward. The average velocity after re-tuning the trigger to the new setpoint dropped to 946fps. still using the H&N 21.14. The setpoint drop-off is now about 125 bar. So, it appears that a quarter turn averages about 25bar change. I'll wait till I receive the 23 grn slugs and recheck velocities after adjusting trigger,,,Again.
One thing, the "ES- " now is 2.9 over 8 shots using the same 21.14 pell. Not bad for my intentions. Actually far better than the starting point.
I'll need to put up a target to check for accuracy. Even though it's a little too high velocity.

That's great! Keep it where you at, test for the consistency tomorrow, it should be done settling. These Airmaks Arm guns are amazing but they like being tuned in a tiny window. Otherwise you will hear it if it's out of tune.

 

[ericf]

Results for today using three different weights of pells using 8 shots over chrono
H&N rabbit magnum II @ 25.31 gr. Slugs. hi 885.3 ; lo 877.7 ; MAD- 2.6; ES 7.4 ; AVG. 883.1
H&N Baracudas @ 21.14 grn. Pells Hi 949.7; lo 943.2 ; MAD 1.9 ; ES 6.5; AVG 945.7
JTS Diablo Exact @ 18.3 grn Pells Hi 989.2; lo 985.3; MAD 1.4; ES 3.9 ; Avg 987.4

I backed off the hammer spring about 1/4 turn to get the numbers. Happy that all three pells perform so well. Accuracy is better than me with all three.
I'll be Leaving it alone. I'm just going to have a good time with it. May end up with a Standard Krait at a later date but UA doesnt have any. Im not sure what tariffs will do to us .
Thanks again for all your help and advice. I learned a lot just by being here.
CHEERS and Happy Labor day weekend.

 

[RoosterCogburn]

Results for today using three different weights of pells using 8 shots over chrono
H&N rabbit magnum II @ 25.31 gr. Slugs. hi 885.3 ; lo 877.7 ; MAD- 2.6; ES 7.4 ; AVG. 883.1
H&N Baracudas @ 21.14 grn. Pells Hi 949.7; lo 943.2 ; MAD 1.9 ; ES 6.5; AVG 945.7
JTS Diablo Exact @ 18.3 grn Pells Hi 989.2; lo 985.3; MAD 1.4; ES 3.9 ; Avg 987.4

I backed off the hammer spring about 1/4 turn to get the numbers. Happy that all three pells perform so well. Accuracy is better than me with all three.
I'll be Leaving it alone. I'm just going to have a good time with it. May end up with a Standard Krait at a later date but UA doesnt have any. Im not sure what tariffs will do to us .
Thanks again for all your help and advice. I learned a lot just by being here.
CHEERS and Happy Labor day weekend.

Awesome. That gun a few degrees of hammer tension are the borderline dissecting disappointment from thrill. Great spot.