At the heart of Speer TMJ lies Uni-Cor technology - a process that bonds a seamless copper jacket over the entire lead core, eliminating the exposed base found in FMJs. The result. Cleaner combustion, reduced barrel fouling, and superior ballistic uniformity. The lead core is fully enclosed within a seamless jacket using Uni-Cor technology The design removes the elements that typically reduce accuracy in standard full metal jacket bullets Minimizes fouling and airborne lead Uniformity in bullet diameters and a consistent heel