Hornady Custom 6.8mm Remington Ammo SPC 100 Grain GMX Lead-Free ammo review offers the following information; Custom-grade ammunition from the factory. Built to the tightest tolerances for peak performance rivaling and sometimes surpassing handloads in many guns. Loaded with Hornady's GMX bullet, this bullet is harder and tougher than a copper bullet and also helps to reduce fouling in the barrel. Hard-hitting and deep-penetrating, the GMX bullet combines monolithic construction with pioneering ballistic design to meet the need for a premium, non-traditional bullet. The mono-metal design of the GMX bullet is crafted from a copper alloy. Harder than solid copper, the copper/zinc alloy has been proven to shoot cleaner, foul less, and deliver consistent, even pressure curves. The tough alloy material routinely retains 95% or more of its original weight and expands up to 1.5 times its original diameter.

Featuring a long, sleek profile with cannelures, the design reduces the bullet’s overall bearing surface and drag, while achieving some of the highest ballistic coefficients from monolithic, non-traditional bullets. Initiating expansion upon impact, the hard polymer tip drives into the hollow cavity at the front of the bullet, creating a mushroom-style projectile as it travels through the animal.