While I will contend that one never needs to dimple for a gas block, I will respect those who choose to do so. I believe in freedom and if you want an unneeded, unnecessary step added to the construction of your boomstick, who am I to judge?
For those looking to dimple their barrels, EZ Accuracy, a “full service gunsmith”, has created a nifty little tool to make dimpling a barrel easy, all without various expensive proprietary tools. Dubbed simply the “Gas Block Dimple Tool” (they really should rename it the “Simple Dimple”, but I digress), the GBDT is a hollow 10-32 set screw that threads into most gas blocks allowing for the simple marking and drilling of a dimple.
To use, remove a screw from the gas block (keep the other one) and install the gas block with the one standard screw. Once installed, run the GBDT into the other location. Then, use the included marking pin to mark the spot and then prepare to drill using a standard drill press or optionally, run a 1/8″ drill bit directly through the center of the screw. If multiple dimples are required, repeat the steps above, just running in the set screw into the now dimpled barrel.
The GBDT runs a cool $14, which is a veritable bargain for such a good idea and easy tool. It can be picked up directly from EZ Accuracy’s website.