Originally Posted By: coyotekillerNEhm1996, I could definitely buy the idea that the rifling had been damaged on those old M1's. I'm guessing they were issued and or cleaned with a steel cleaning rod.
Spot on! Most likely a jointed steel rod (as was issued in US Army)at that. There are those who promote the use of (solid) steel rods as they do not tend to pick up abrasives on their surface as do the coated rods. There is substantial evidence to support this theory, i.e., when using valve grinding compound to seat the valves in an engine, the compound is embedded in the block (the softer of the two metals) and actually grinds the valve (harder), but steel on steel has to wear the barrel more than clean plastic, especially if it cannot contact the bore.
Having said that, I choose to use the coated rod, which I clean to (hopefully) remove any abrasives between each use. I also choose to use a guide as an additional safety measure to protect the throat (or muzzle on M1's & others which are necessary to clean from muzzle). Akin to belt and suspenders? Maybe, but I sleep better at night that way. 
Regards,
hm
