I think its every 16th arrow will be random GT Arrow. @Blood Asp might correct me.Or I could change the following line in the Gregtech config file under the General section to some other value, not sure what, though:
I:SkeletonsShootGTArrows=16
I know there's a way to turn them off or at least lower the chances of running into them. If anyone knows how this config file option works, please let me know, if possible, I'd like to disable entirely skeletons shooting GT arrows.
Cheers ...
BrickVoid