Berger's BR Column, Target Flat Base bullets are recommended for benchrest shooters looking for consistent, accurate bullets. These bullets have been under development for 4 years and are specifically designed to have the widest and lowest tune valley available. Every time these bullets are in a production run Berger balances the lead column to achieve the optimal balance for that lot#. Due to slight variations in copper and lead materials one lot may weight 64.8 grains while another lot may weight 65.1 grains. This lot-to-lot variation is acceptable because Berger found that the most accurate bullets are the best balanced bullets. By achieving the optimal internal lead column height Berger can create bullets with optimal balance. The overall bullet weight is a by-product. The weight in our description is an approximate weight. This is not loaded ammunition.