MemberJune 12, 2016 at 2:10 am21 Bullseyes
My first instinct is to suspect the action bolts/screws – Do you have access to a torque wrench? I would start with 35 in-lbs and work up to 45 on the polymer stock (assuming that the T3X is similar to the T3 in this respect).
I also look at the bench set up, bipod, bags or rolled up jacket? In any case if he can eliminate the variables that contribute to an unstable condition we can start digging deeper.
What caliber and model T3X is he shooting? (in case the ammunition he is using is marginally stable for the barrel twist). These are just a couple thoughts, your friend's T3X should perform consistently so I would like to hear how things go.