That is not a Glock-unique problem, though.
No, but polygonal barrels seem to gunk up faster when crappy bullets are in play.
Most people equate harder cast bullets with less or no leading. That is an ignorant oversimplifcation.
I suppose it is but I've seen it go both ways, although I suppose at the time what I saw with the softer bullets also could have been due to sizing issues. Regardless, bad bullets = lead problems.
-Mike