I was thinking about using a dedicated frame with the Mech Tech CCU, but was wondering a couple of things: 1. Do I need to re-register the weapon as a rifle if I add the basic glock ccu to a dedicated frame? What about if I add a stock? Front grip? I'm in Washington state if that matters... 2. Who makes the best frame: Glockmeister, Lone Wolf, or Glock (used)? 3. Any advantages of using a g17 frame over a g19 frame? 4. Any opinions?