Originally Posted by Tordenskiold1721
Hand and a half Estoc fighting during tournament. Note how the combatants are searching for the opening in the opponents plate armor
That is correct, but searching for openings is very different from the common perception of piercing the armor - which is plain impossible.
On subject of mail - there have been many, many attempts at piercing it, so generally speaking, a very thin blade in most cases fails to split even one ring on a high quality riveted mail. In few cases when it was able to, it certainly did not produce anything even close to a disabling wound. In order to produce it it would have to split many, many rings - remember, usually there was a gambeson under the mail.
Fortunately for the estoc owner, great majority of fighters didn't have such armor. So estoc was potentially quite effective in the battle, but not because it was able to pierce the plate.