From all the advice given from a pervious topic I what to share this with the people that are interested. Both my air arms stringers seem to have a poor firing cycle, start with chrono results before strip,
Pro-sport = 792, 789, 798, 804,803,821,799,799,804,794
TX200 = 824,819,804,798,801,808,802,802,799,802
Air arms pellet 8.4 with a 4.51 head size.
Now stripped and found spring end poorly finished, spring guides not bad, inside compression cylinder needs work. I will added more chrono result once relubed and polishing has been done and the Tinbum kit has been fitted to the Tx.