Current Rule:
Chain mail must be made with links no larger than 1/2" rings of 12‐gauge steel or bronze; 3/8" rings of 14gauge steel or bronze; or 1/4" rings of 16‐gauge steel or bronze. Chain mail made of sturdy links that fails to meet the requirement of AC3 will be AC2, e.g. shark mail would fall into this category.
Proposed Rule:
Chainmail armor is constructed of interwoven metal rings, and the ratio of the diameter of those rings to the width of the wire used, known as aspect ratio, determines its strength. The maximum ring sizes for standard European 4-in-1 chainmail armor, both butted (including welded) and riveted, are given below. Chainmail armor made of sturdy links that fails to meet the requirements of AC3, e.g. shark mail or butcher's mail, will count as AC2.
Butted Mail must have an aspect ratio of 4.8 or less, as follows:
12g rings must be no larger than 1/2" (0.5") or 12.7mm
14g rings must be no larger than 3/8" (0.375") or 9.8mm
16g rings must be no larger than 5/16" (0.312") or 7.8mm
18g rings must be no larger than 3/16" (0.188") or 5.8mm
Riveted mail must have an aspect ratio of 7.5 or less, as follows:
12g rings must be no larger than 3/4" (0.75") or 19.8mm
14g rings must be no larger than 9/16" (0.562") or 15.2mm
16g rings must be no larger than 7/16" (0.438") or 12.2mm
18g rings must be no larger than 5/16" (0.312") or 9.1mm