Distance fired / projectile used / velocity ? was NIJ test replicated ( which uses a single shoot test barrel / jig ) ? FYI the clay must have steel ball dropped into it from prescribed height and is the measured to obtain proper depth / your replication is far from valid and somewhat miss-leading if your looking to obtain true data & clay reacts differently if not kept at prescribed temperature / plus the plate is supposed to be shoot with a 30-06 M2 AP round which is the current prescribed test round
gadget