99.9999999% I've heard great things about JES rebore. However, years ago, I bought a Rem760 from JES that was rebored to 9.3x62. Very cool in theory but I had issues getting it to shoot. Long story short, after multiple factory ammo and reloads, I bought a No GO gauge...... and it chambered. I cant say I know what that means 100% but it spooked me enough to swear-off ever buying or ever having a rebore done or owning one.
That said...I sold the rifle to someone who had more faith than I......and I wish I still had the rifle to continue the detective work....
If that was the case I’d have bet a dollar he would have taken it back, taken a thread off and made it rifle.
He did a 35 Newton for me. Had a rough chamber. 2md time around it was perfect though.