I have several carbine length gas seystem AR uppers in 5.56 with A-2 sight towers

Tired of dented brass and 1 o'clock ejection I purchased a Ruber City Armory adjustable gas key and installed it on an M16 bolt

Simple instructions supplied with the key were simple/very easy to follow and after the 4th round the rifle ran the rest of the day without a single issue

Ejection is now 3 o'clock

With over 500 rounds through the test rifle I decided to add an adjustable gas key to another rifle with an A2 tower

But this time as a DIY project I decided to make my own adjustable gas key

I pulled a gas key off of an M16 bolt and Rockwell tested it......26C....very drillable

I set it up in a mill and simply drilled and tapped 8-32 into the same location as the Ruber City Armory key

Installed 2 set screws and proceeded to get the same great results from this DIY key as the store bought Ruber City Armory adjustable gas key