Merc Armor Break feels bad

I don't know if the time extends in later levels, but I have a level 8 Mercenary, and when I use my skill to break an enemy's armor, it does not last long enough to capitalize on. I break the armor, switch ammo types, fire 2 or 3 shots, and then the armor comes back. it feels bad, like why should I even bother?

The time just increased from 6 to 12 seconds I think with the last patch. Have you tried it since or is this complaint post patch? I ask because I'm planning on adding Corrosive to my gas grenade when I get home tonight.

Envenom + Corrosion helps with Armor Piercing ammo, but later down the line it gets REALLY easy to break armor if you use Gas Grenade + Corrosion, it being extended to 12 seconds has also helped.

IMO, Armor Piercing ammo is not that great in general.

90% of the merc crossbow skill are useless.