My VX6 7-42 had problem with the turret getting stiff then locking up. Sentbit in for repair. Worked for awhile then happened again. I only use NF now. NX8 4-32 mostly. Had a ZCO 4-20, sold it, extra weight wasn’t worth it.
When developing loads to shoot 5” groups at 1000 yards you have to eliminate all the variables you can. Scope variance is step one. Get a good one and lock it down. I use green sleeve bearing locktite under rail and/or rings, blue locktite on base screws. I’ve been using rosin on scope rings to eliminate sliding issues.