clearstream
(He, Him)
I wasn't aware of that ruling. It's clarified in the DMG errata that mundane ammunition fired from a magic bow counts as magic. That seems good to me.Magic ammo? Just use a magic bow.
The comparison is then as always, the caster's magical attacks are magical from day one. The archer needs to find a magic bow. That said, I feel like an archer at tier 3 should be assumed to have one!