http://wiki.project1999.com/A_Drolvarg_Sentry
Charmed this has around 298ac naked. NPCs will wear most item slots (only 1 bracer). A full set of bronze minus 1 bracer adds another 103ac. Agility buff will add another 20ish. Raw AC buff depending on the class can add another 50ish. 173 real ... raw ... AC.
298 + 178 = 476ac
That's almost as much AC as this:
http://wiki.project1999.com/Veteran_Icecaller
Aside from the difference in levels and the relative impact it has on hit distribution - a green con charmed dog will take hits as well as a Kael arena baddie.
And if you charm one of these from seb?
http://wiki.project1999.com/Froglok_Krup_Knight
Base AC of 421 + 176 ... almost 600 raw (not visible/displayed) AC.
For any shaman who's ever duo'd with a summon pet tank (mage/necro) class or even just used their own dog to tank - this becomes very obvious. A properly buffed summon pet without gear (30 innate regen a tick) is easier to heal than a fungi monk. Give the pet gear and it's pretty amazing.
I almost feel dirty for letting the cat out of the bag ... but that's just how the game has always been coded.