i had a customer bring one in my shop before this past whitetail season.
with the same failure.
i recommended he go and talk to a friend of mine that does custom welding
from boat tee-tops to 2" iron plate marine transmission mounts.
he also instructs welding at the local vo-tech center.
the customer was frantic about the accuracy of his .308 standard contour
it was less that 2" @200yrds 5 shot group, of course with cool down time between shots.
anyway, it was done and not a .002 difference in accuracy.
i guess it all depends on the experiance and knowledge of the art of bonding two substances together the right way.
and he only charged $30, he also told the customer if it affected the accuracy, he would replace the barrel!!!!. cool thing is, the welder don't even own a gun and did'nt have a clue about barrel harmonics.
he just knew what had to be and not to be done.
thats a real welder, the kind that can weld-up the crack of dawn to a broken heart.
and don't forget about the windshield wiper thing

but it's all good if you like the jb weld fix, thats just another option