Okay I was doing a google search about home made darts. I found out I have been wasting good cones for years now. My find was a guy using BD pen needles out case for dart cones with a nail or wire inserted into it. I use these every day and it never occured to me. Slap to the back of my head. They have a slight lip that need to come off I think. With the lip they are .625 and without .5625 or 5/8 and 9/16.