Easy enough to remove the plastic OEM front sight and a hex nut front sight but how do you remove a metal Glock factory crimp-on front night sight? Looks like it is made either by Trijicon or Meprolight but it doesn't matter. I just want to get the thing off so I can install new sights. It's on a G23 by the way and they were on the gun when I purchased it new. Thanks!