Anyone use this technique for breaking in a new barrel?  A guy at the range was telling me to put moly lube on a patch, run it through the barrel a few times and then shoot it leaving the lube in the bore.  He advised that the moly lube would fill in the imperfections in the barrel???

Never heard of using moly lube to break in any barrel. That kind of defeats the purpose of barrel break-in doesn't it? I mean if you shoot and clean and shoot and clean, etc., you're cleaning the moly lube out of the bore, right? IMO, you don't want moly lube to fill in any imperfections in the bore, you want high speed metal jacketed bullets to remove and polish out any imperfections in the bore.

I don't think it would hurt it, but it seems to me that using moly lube would unnecessarily prolong the barrel break-in period.

I'd save the moly until after the barrel is already broke in. Then you could use moly coated bullets if you're so inclined.

OCTJMO
ICBW