I've shot Wolf ammo here and there in 223 and 45. As Tom mentioned, at 50yrds it was all over the place within a 5" group(223 in my case). At handgun distances ofcourse the accuracy variances are less noticeable. The other reason why Wolf ammo is so dirty is due to its steel case. In a brass casing, after firing, it will fire form to the chamber, meaning expand to the size of the chamber it was fired out of, therefore minimizing any gas and powder discharge from going back into the chamber and action. With steel casing, fire forming does not occur as much therefore allowing more crap back into the chamber area. Hence more cleaning!
Some folks say that steel casing causes more wear on your chamber, thus being bad for your gun, but this I am assuming is over the course of thousands upon thousands of rounds. Just food for thought.