According to Don Zutz in The Ducks Unlimited Guide to Shotgunning much depends on method or barrel jointing (brazed is preferred to soldered) choke constrictions and size of shot used (smaller shot is better then larger pellets). I did see Model 100 or Model 200 in fine exterior shape with scratches in choke area of the bore and could not figure out how those got there (neither could people at shop I seen it at).
Our shooting expert HomelessJoe suspects that much of barrel damage occurred when steel shot was first introduced. The shells did not have appropriate shot cups nor were not well water-proofed. Moisture would get in leading to shot clumping which did the actual barrel damage. I suspect he is correct on this.
