One of the biggest causes of accuracy loss over time is barrel wear; specifically throat erosion. Tubb's Throat Maintenance System consists of a series of 50 bullets coated with a special polishing compound that is designed to smooth out the section of barrel directly ahead of the chamber. The result is a smoother throat and restored accuracy. For use only after using Final Finish Bore Polishing System. Use TMS bullets with starting load data with fastest burning powder for specific caliber.