Shotgun.

Realizing that you don't need to be all that accurate with a shotgun and the damage potential of the weapon, Lisa fired at him first. Both of the shots she fired at him hit in the chest. He had no time to react and was thrown from his horse by the impact of Lisa's deadly accurate shots.

Lisa then switched targets to revolver guy. Having at first been caught off guard by Lisa's decision to fight he was now only drawing his weapon. Both fired at the same time. Lisa's round narrowly missed. However, the return shot was on target.

Lisa felt the hot metal rip into her chest. Lisa was thrown to the ground. She lay on her back struggling to breath. The two remaining enemies approached.

"She got the drop on us, boss!" stated rifle guy.

"Not me she didn't!" revolver guy growled back.

Lisa watched helplessly as revolver guy pointed his weapon at Lisa's prone form. He then fired it again and again into Lisa, ending her life.