nother weakness of maille armor is its vulnerability to thrusts from pointed weapons, arrows, and crossbow bolts, which could easily split butted rings. Riveted rings of course were significantly more resistant but could still be pierced if the projectile hit with sufficient force. (Note: Modern day tests made by various reenactment groups have demonstrated that a bow fired arrow will punch holes through maille constructed of butted steel rings while maille made with riveted steel rings will resist the same arrow.)
70lbs, 15 feet: 2 out of three arrows pierced the maille/gambeson and imbedded themselves in the pell. The third arrow broke two links but bounced off, stopped by the gambeson underneath.
^ This is with the finest modern day chainmail available. So the "heretic" is not wrong. Chainmail was used to protect against slashes.