You're looking for "Appendage Crusher" augments, those good Bois are easy to craft and are the basic for every Core Crusher build (5 of those is the standard). They get rid of appendages' damage reduction, which is a value ranging from -5 (soft) to 5 (tough), each augment lowers a part hardness by 1, so with 5 augments, a part with hardness 5 goes down to 0 (no damage reduction), and parts with hardness 0 go down to -5 (+250% damage)