C.O.A.L. ?

Remember, that will change with each different bullet type or brand you use. Even within the same brand (lets just say Hornady A-max) the length of the individual bullets themselves can vary a few thousandths.
A better method is to use a bullet gage. This will allow you to measure your bullet or your loaded round to the ojive. That point on the bullet where the curved section intersects the bearing surface. This give you a better measurement than using the tip of the bullet.
www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-comparator-inserts/sinclair-insert-style-bullet-comparator-prod34014.aspx

This is another cheap tool which does much the same:  I have two of these

www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-comparators/sinclair-hex-style-bullet-comparators-prod83792.aspx

When you have been around top bench rest shooters for a while, you pick up a lot of good tips. I have often said that if general run of the mill shooters, reloaders, hunters could go to one or two bench rest matches and question some of the competitors, they would increase their learning curve ten fold! Its like being a newbie and going to the Kentucky Challenge------------------ I know it worked for me when I got involved in precision rifle shooting and when I joined an archery club! You need to associate with people who have BEEN THERE AND DONE THAT! I am only happy to share what I have learned from others and by practical experience, with members here.