I went to my local Hardware Store yesterday looking for a drill bit that centered itself in a chamfered hole like on a Hinge or Striker Plate on a door. You've all seen them. Not in stock!
But the guy who was helping me told me that the hot tip and what they normally had in stock was a tool made by a guy in Minnesota named Vick, His tools are called "Vix Bits." He told me where to get them in Ventura so I went and purchased a #6 and #8 tool. Not cheap at $13 each but I could see that they would do the job better than anything I had used before.
The drill bit is changeable and the plunger that shrouds the bit is the moving part that gets pushed up to allow the bit to go deeper. Also that plunger doesn't rotate with the tool so you don't have to worry about gooning the surface of whatever you are drilling thru.
The whole reason I got these is because I needed to locate the Buttplate and Rear Sling Swivel on my NRA Sporter Replica and any movement in either of these rather expensive piece parts would have ruined the stock.
They worked perfectly on the first try!!!
Well worth the cost. You can google them as they are sold on Amazon and a variety of other places.
Randy