It had already been established that he is a level 5 Limb Exploder, thus making him nearly invincible.
All he has to do it blow up IB so it flus towards his enemies when he wants to beat a long range spell or attack, summon the dragons, then regrow it.
On a side note, does anyone else think Apgami is the photo lens esper behind the rumor site? They mentioned that esper in the last Railgun arc, and now he's suddenly appearing in this next arc knowing who org Misaki and Misaka are. Not only that, but he's had inside info in the early novels that he shouldn't have known otherwise.