Our custom made 5/16" solid carbide end mill bit is optimized for high speed precision milling of 80% lower receivers with a handheld router. The upper portion of the end milling bit is reduced to 1/4" to fit standard routers, while the shank and cutting surface are 5/16" diameter to allow for easier milling with minimal deflection. This product is also proudly made in USA.
NOTE: This is the only 5/16" high speed end mill that will work properly with Easy Jig Gen 2. Using another type or size may cause damage to your lower and jig, voiding the warranty.
For almost any application, the key to a successful 80% lower receiver milling job is to go S ... L ... O ... W. We have seen many instances of people running this too quickly, resulting in a broken End Mill. To avoid this...please go very slowly when milling out your 80% lower receiver to avoid this.