Talk:Excalibur (Warframe)/@comment-13260075-20130727233417/@comment-9934986-20130729191458

Avalon gives you a 25 extra shield regardless of your Redirection mod. The health reduction, however, is taken after any positive modifiers have been applied. The health is subtracted from your total health with bonuses, making the helm rather detrimental as you grow in power.

It's overall a rather minor nerf, however, so if you like the looks go for it.