I did the same thing. your preload adjust the hammer spring tension (3/16 wrench) which max is 7-1/4 CW turns from full CCW. if your saying 6-1/4 your almost max on spring adjustments. the hammer throw adjustment (1/8 wrench) adjust how much the hammer hits the valve stem alowing for more or less air flow. if your hammer throw is 0 full CCW your allowing the max air to flow , the more turns CW you make shortens the amount the valve is open lowering the flow of air. the hammer throw has 12 full CW turns from 0 CCW. the more turns CW at max spring tension will lower your fps down to almost nothing.
now adjusting my Prod full max hammer spring tension 7-1/4 turns, gave me best fps shots, but,, still no where near yours, that is with using a .094 TP or the .101 TP and shooting 14.3g pellets with a fill of 2400 (my sweat spot).
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