@Telephonepete That string looks pretty good. The groups are not terrible either but I would want better too.
There's a lot of things to try out, but to help narrow it down if you haven't done so, I like to shoot at competition cards with a single shot per bull. That way I can see any patterns clearly throughout the fill. For me, that helped to reveal that some ammo was not as consistent as I thought. This also helped to figure the optimal start and end fill pressure for accuracy.
I only have .22 Krals but they strongly favor JSBs. Also, my Krals are most consistent from 2500/2600 psi down to 1800 psi or so.
In both of my Krals, I changed out the hammer spring to shorter and stiffer springs to give free flight to the hammer. This did help to eliminate fliers and improve the guns overall. I also polished the barrels in both of them. This also helped with accuracy and to decrease how often the barrels fouled.
From the factory, my NP03 needed the polishing more, it was very accurate for about 20 shots then the bore would get very dirty and require 7-8 pull through patches to clean. It now can do about 100-200 shots and needs 1-2 patches to clean.
My Puncher Mega is more accurate, unsuprisingly. Below demonstrates the progression as I improved it. First pic shows 25 yard 5 shot groups with JSBs from my Puncher after changing the hammer spring. The second pic is testing different ammo after bore polishing at the same distance. The last is a 25 yard card after changing the hammer spring again and I realizing that JSB heavies worked better than 15.89s. My Mega may do slightly better now as I have a better bipod and worked on the trigger.
Good luck with the NP02!
View attachment 362044 View attachment 362045 Thanks very much. Just removing the barrel band altered things but then I suppose it would. I straight away took it as arranged previously to my Nephew and we shot a couple of groups. It is just possible that the barrel band may have made things rather better. Anyway he is removing the anti tamper and I hope will drop it under 12 ft lbs to make it legal and anything else that occurs to him. He has a empire xs that he is always messing with.