Danl, you'll be getting some experienced answers here from other members - I have too high a ratio of 'book larnin' to experience.
From what I understand, it depends upon the weapon. For example, note this advice re: the
chrome-lined AR-15 barrels from Bushmaster -
http://www.bushmaster.com/catalog/barrels-accuracy.html :
"Q. What is the proper "break-in" procedure for a chrome lined AR barrel?
A. After firing a couple hundred rounds, the chrome lining will "polish out" from its light, flat gray, factory-new look to a brightly reflective, polished appearance. During this break-in period, excessive cleaning with solvent or brush should be avoided as that will only prolong the time (and number of rounds) it takes to achieve the final "bullet polishing" of the barrel."
Ironically, this is 180 degrees from the gunsmith's advice you received. Does the chrome lining account for this difference? I don't know, but it seems unlikely.
If it was me, I'd also call the manufacturer, request an owner's manual, and ask their advice as well. [If it's a custom barrel, I suppose you could call the manufacturer of the barrel.] In my experience, most of the factory reps are good, helpful people. Good luck.
[This message has been edited by Jeff Thomas (edited 02-05-99).]