Review on 🔧 SPEED TIGER ISE Carbide Square End Mill - High-Quality Micro Grain End Mill for Alloy Steels/Hardened Steels - 2 Flute - ISE5/16"2T - Made in Taiwan (1 Piece, 5/16") by Danny Rogers

I have used and abused this drill bit to cut and route the 2 lower ARs on my drill press. At the end of the second he started to blunt. However, I abused it when cutting aluminum and it worked really well. Remember that you will need to increase the speed of the drill for it to work properly with these bits. It still cuts, just dulled a bit by the amount of use. Much of the material was removed to complete 80% of the lower receivers. I would recommend and will definitely buy more for future builds. I had no problems with it breaking, luckily I only had one. Also the length is great for the work I did.