Master Exploder

Master Exploder is an achievement/trophy in the Red Dead Redemption Liars and Cheats DLC pack.

Description
"Complete the Explosive Rifle Single Player Challenges."

Red Dead Redemption
Explosive Rifle challenges:

Rank 1: Buy an Explosive Rifle from the gunsmith in Blackwater. It costs 5,000 or 10,000 dollars depending on whether or not the player decided to spare the life of Abner Forsyth in The Prohibitionist.

Rank 2: Kill 5 enemies taking cover. This is fairly easy to achieve. Simply go to any hideout and shoot 5 enemies while they are in cover.

Rank 3: Kill 3 enemies with a single shot. This is where it may get tricky, but here's an easy way to deal with this: Go to the Gaptooth Breach, dress as a Treasure Hunter, and simply tie up three and place them in a pile.

Rank 4: Kill 2 wild animals with a single shot. This shouldn't be too hard, there are wild animals everywhere. I would recommend going either east of Escalara or to Tall Trees which is filled with wild animals to get this rank.

Rank 5: Obtain the U.S. Army Uniform and kill an enemy with the gun while wearing it. Again easy to do, just acquire the U.S. Army Uniform, wear it, go to a hideout and kill an enemy.

Undead Nightmare Disc
Explosive Rifle challenges:

Rank 1: Save Rathskeller Fork.

Rank 2: Kill one of each undead type. Best to go to El Presidio, as all four types spawn there, if you're lucky you might even get them all in one shot.

Rank 3: Kill 3 Undead with a single shot.

Rank 4: Kill 2 wild undead animals with a single shot.

Rank 5: Kill one undead as Zombie Marston.

Trivia

 * The title is a reference to the song Master Exploder by Tenacious D.
 * For Rank 3, the easiest was to accomplish this task is to head to Gaptooth Hideout dressed as a Treasure Hunter. Simply tie up three of the Treasure Hunters, set them in a pile and shoot.
 * For Rank 4, beat any Hideout and a large amount of Vultures will circle a head. They fly in a pattern so watch as they all group together and fire. Firing into the middle of a pack of wolves before they are aware of the player's presence can also yield multiple kills. If they come after the player, try shooting between the two wolves that are closest together.