@flyingbug - if the drill bit that you receive does not seem to be removing material from the welded collar (ie: it spins, but does not make chips) please let us know. You can PM here through the forum, or send us at email sales@hbindustries.net. We will get you taken care of.
The welded screws earlier this year were not bad at all, but around July we started seeing the carbines first, then the pistols too, having really hot deep welds. They still seem to be coming in that way, and like others in this thread can attest to, you will likely have to drill practically all the way through the collar/screw, almost until you think you are about to hit the topside of the sheetmetal trigger housing. These welded screws are a pain, but totally worth it once you get the new trigger parts in. You can do it!