Hello Bill , when buying a Damascus barreled gun on line ,I always contact the seller and explain that I am interested in bidding on his gun and that I own a Hosford Barrel Wall thickness gauge and that if I bid and win the gun ,I would need to have a five day inspection on the gun to take my time and measure the barrels and if the Barrel walls checked out good then I would keep the gun ,so far no one has ever turned me down ,remember these fellows are interested in selling their firearm ! With that said of course everyone wants perfect bores but I prefer pitting to honing and with this gauge if you really take your time you you are able to measure most pits as the tip will drop into the pit ! I am adding a link
https://www.youtube.com/watch?v=1jQZn4kohH4 ,to the Hosford Gauge ,they seem expensive but ,the cost is well worth it if you purchase a pricey gun with bad barrels and find out about it later ! Hope this is of interest to you , I am not associated with " Hosford and Co. ,just a consumer that is well pleased with this product ! Best ; Russ