By using light-for-caliber bullets, velocities are high and by using pre-serrated, all-copper bullets engineered by Lehigh Bullets in Quakertown, PA, expansion is very wide. The bullet actually opens to look like a four-bladed propeller. This wide expansion keeps penetration to a moderate depth, but the bullet cuts a wide and devilish wound cavity. The bullets perform well against intermediate barriers because their expansion is generally induced by a liquid-based material, like tissue. If there is a downside to these bullets, it's when they reach total expansion, they tend to turn on their sides and slice through tissue as opposed to driving nose forward. Tissue damage, however, is still extensive.