taipan power adjustments and accuracy

[rangur1]

as for the OP, i had wind 10+mph. i also ran 4 different pellet brands/ weights. i was just doing basic groupings. farting around. when i try this again. i will tune HST back around 50 FPE like it came from dealer. i tuned it down to avoid putting holes in my friends garage/storage shed. when i pick up another gun. it will have this purpose, and my taipan will be dedicated to it's rightful job once again! LOL!

 

[Beach-gunner]

I have Taipan Vet shorty in 22. Personally I only tune with HST adjuster from Donnyfl. Just write down the turning adjustments you make to desired speed while shooting over crono each step of the way. When you want to get back to factory follow your note card. I’ve tuned mine from 825fps with JSB 18.1gr to 525 FPS with same pellet. Now we all know that diabolo pellets will de-stabilize as they slow down, so with the 525 FPS tune my range is 15 to 35 yds with good enough accuracy to dispatch pests. While squirrel hunting I tune back to 825fps as I typically take shots 40 to 75 yards with good accuracy.

 

[octavius]

I did some chrony of veteran std cal.22 The first picture is with JSB Jumbo 16grains speed tuned to 905fps and second one if with JSB Heavy 18grains tuned to 921fps.

Something is interesting. Why is so big spread from begin? I filled the gun in both instances to 235bar. Speed seted with HST for JSB Jumbo is slow with jumbo pellets - there is bigger deviation. But on second picture I crank at up the speed of JSB HEAVY to 921FPS but why is so big spread on begin?? Let say after 25 shots the regulator running well but why not from begin? Accuracy is better from 180bar. 

Sorry for metric unit but I think graph is clear.

 

 

[octavius]

Nobody replied. It is OK? Something is different when I compare it with my cricket string

 

[rangur1]

This is an old post of mine from well over a year ago. But from what I see , the hst is maxed and with the higher fill pressure seems to strain it until your cylinder pressure drops down a bit. Lowers the violence of it if you will. I dropped my reg to 130 bar and saw no drop in power on my taipan. I would back you reg pressure down to 135. Push the hammer spring up to 900 fps and see if the difference at the beginning of a fill calms down. 

 

[octavius]

Thanks rangur1. I've no clue which pressure is set on regulator. I intended to shoot with 18gr and 16gr jsb pellets so the speed I would use is 900fps/274mps

Do you think my regulator is set to high from factory? There is any number on his body. I have regulator tester but it is for cricket. Veteran has smaller diameter of the regulator so can't use it without bigger oring...(probably) 

But what I can't understand why he is regulating better from lower pressure? 

 

[rangur1]

when you crank up the HST towards the maximum. some how it creates instability. my taipan reg was set at 152 bar. i turned it down to 125 bar added a plenum and had no increase in power , but had a 50% increase in shot count per fill. except at very highest setting. that shot count remain unchanged. 

i just read your charts , the heavier pellets were more stable , no surprise at those speeds. if gun is tuned correctly , spread in velocity should be around 10 fps / 3 m/s mine were with 25 cal 34g jsb velocity spread of 8 fps or 2 m/s . that is what the gun does when close to balanced. 

ALSO - i only pressured gun to 220 bar and shot from there , this is where the lower reg setting may help you , start at 220 bar , shoot down to power drop , which now should be 140 bar. see how many shots and spread. then if possible , tune reg to 130 bar. then repeat full shot string starting at 220 bar and it should go until about 110 bar. if you do not wish to remove the reg. then i would say dial down the HST to 880 fps/ 270mps for the 18g jsb. shoot string again from 220 bar until drop off. check and see if gun settles down. i suspect you have it cranked up to high and thats why it takes 20 shots to settle down and become consistent.