Bang the bullet - Barrel
You can still use a Missed card like normal if the barrel fails. From the rules:


  Example. C is the target of A's BANG! C has a Barrel card in play: this card lets him “draw!” to cancel a BANG! card. So, C flips the top card of the deck and puts it on the discard pile: it's a 4 of Hearts. The use of the Barrel is successful and cancels the BANG! If the flipped card were of a different suit, then the Barrel would have had no effect, but C could have still tried to cancel the BANG! with a Missed! card.