Ah, the Dremel tool... or it's cousins..
If you want to use a real Dremel, get the kit with the variable speed unit. The one that has a flex-shaft attachment is nice, but most people don't get alot of use for the flex tool - seriously. I've worn out two Dremel or Dremel-type units over the years, and they work pretty well.
For intricate work or action jobs, don't do it! Use hand honing techniques with some hand stones instead and buy a stoning fixture whenever possible, and the Kuhnhausen series of books from Amazon.com or Brownell's is an awesome help too. I can't say enough about Kuhnhausen. God bless him.
DO NOT buy the cordless Dremel stuff. Not enough power, and the battery runs down too fast. If you are willing to spend the money and need heavy duty power, the Foredom tool (which is a flex-tool only kind of setup, with hanging device -available from Brownell's) is the way to go. These are very hard to wear out. They will accept the 1/8" shaft accessories just like the Dremel or similar tools will. There is a learning curve to the accessories - stones, sanding wheels, carbide tips, etc. These type tools are very handy for initial fitting of some 1911 parts (beavertail grip safety, mag well openings, polishing feed ramps, etc. but I would stay away from the trigger, hammer, and sear parts for sure, and also the inside of a S&W revolver with them for sure!
Experiment alot on scrap material before you quickly go after a gun part with them. Good luck, and be careful...