I would say any bullet that is inconsistent would be the worst. If using a solid for penetration or a vmax for vaporization I want it to work within its accepted design parameters.

I would actually lump the original X and original BT into the same place for worst, the X due to hideous accuracy and the early BT for inconsistent terminal performance. Obviously both have taken their lumps and were willing to modify designs to meet the demands of the market. Whether you belong to the "DRT" or "make two holes" school of thought the products on the market will match your expectations.

Hunt hard, kill clean, waste nothing and offer no apologies.

"In rifle work, group size is of some interest...but it is well to remember that a rifleman does not shoot groups, he shoots shots." Jeff Cooper