The Austrian firearm manufacturer Glock advises against using bare lead bullets (i.e. with no jacketing) in their polygonally rifled barrels, which has led to a widespread belief that polygonal rifling is not compatible with lead bullets. Firearms expert and barrel maker, the late Gale McMillan, has also commented that lead bullets and polygonal rifling are not a good mix. Neither H&K nor Kahr explicitly recommend against lead bullets in their polygonal rifled barrels, suggesting that there might be an additional factor involved in Glock's warning. Kahr warns that lead bullets can cause additional fouling and recommends special attention to cleaning after their use. While H&K doesn't insist on a copper jacket, at least one well-documented catastrophic incident in an H&K pistol may be related to this issue. Furthermore, Dave Spaulding, well-known gun writer, reported in the February/March 2008 issue of "Handguns Magazine" that when he queried H&K about their polygonally rifled barrels that they commented: "It has been their experience that polygonal rifling will foul with lead at a greater rate than with conventional rifling."