IMO, two things contributed to the Swift's barrel-trashing rep - The relatively softer barrel steels of the introduction era (why Winchester quickly changed the barrle steel, IIRC); and the SOP of varminters to keep shooting to gun until not only was the barrel too hot to touch, but the heat had also expanded throughout the action too (they had a LOT of target availability in those Prairie Dog towns) - which overheating softened the throats and first few inches of rifling, causing a burnt/crackled-looking surface atop the lands that hadn't been washed out.
We don't hear so much about it today, despite comparible speeds from the .22-250, most likely due to better steels, the abated Swift popularity/use, an less-heated shooting to lower target availability - plus, some dogtown shooters actually take along water tanks, to flush/cool the barrels as they shoot (hard to do, when on foot.
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