[quote=@Burning Kitty]
I know the Ancient Drone weapons can pierce the shields of Anubis' mothership. Don't know why, I am assuming deus ex reasons. 

Could a Proton Torpedo could pierce it?
[/quote]

Well, that was also when Anubis had a completely rebuilt Mothership. I'd assume that his shields are [i]good[/i], but certainly not invulnerable. Especially to alternate-universe tech. They're optimized against lots of imprecise energy attacks, ie, Goa'uld staff cannons. Things that are more concentrated will do better. Of course, unless you expend a large amount of narrative effort, nothing will take out the shield in one hit.