Defiance Free to Play

To complete the Master Gunslinger III pursuit, you need to accomplish the following tasks:

- Use pistols to kill 5,000 enemies
- Reach skill level 10 in Pistols
- Fully mod a pistol

Progress made previous to this DLC is counted toward your pursuit progress. If you have already accomplished all of these tasks, the pursuit should complete right away, although the achievement may not unlock until you gain another skill level in the Pistol skill, simply get a pistol kill, or log out and log back in.

One of my favorite places to get pistol kills is at the Kinship Plaza event. It's quick to do and you can rack up 50-60 pistol kills per run-through, and you can get a bunch of XP and keys while you're at it. But there are many, many places to grind out pistol kills. Just do events that you like.

EDIT: Thanks to Mobius Evalon for the tip that Yuke Liro arena is a great place for grinding pistol kills. Get yourself a decent pistol with a high capacity magazine and go to the Liro arenas at the Diablo Station fast travel. Play the Yuke arena and go nuts on the skitterlings in waves 3 and 5. He reports 230-260 per go with this method. It's also probably the best route to go if you have already reached level 20 in the Pistols skill and need to start a new character to get this achievement.

A good way to level up your Pistols skill is to do Warmaster major arkbreaks. After the armor breaks on his right arm, wait until he jumps up and hangs from his arm and switch to a pistol like the Wolfhound. It has a large clip, fast rate of fire, and large critical hit bonus. Drop a damage spike, hit your Overcharge, and go to town on his arm. You can rack up huge damage this way.

For the modding requirement, you can find pistol mods at the vendor in The Crater. If you don't want to wait to put great upgrades on a great pistol, you can just acquire a crap pistol, go to The Crater Vendor and buy a cheap stock, barrel, clip, and sight. Attach all four to the crappy pistol and you'll have this requirement done.

NOTE: As usual with this game, something is broken. If you are already at skill level 20 on Pistols (max level) then you cannot gain another level in the Pistol skill. The trick here seems to be to log out and then log back in. This seems to be giving most people credit for the Master Gunslinger requirements.

NOTE: Solario32 has noted that you may be able to get credit for your pistol kills/levels by logging out and then back in. I was able to get credit for the kills after simply getting a pistol kill, but didn't get credit for the levels until I leveled it from 14 to 15.

NOTE: Several people have reported that even though they have gotten credit for the Master Gunslinger pursuits, they are still not getting credit for completing Master Gunslinger in The General pursuit, which could be a huge problem in unlocking that final achievement. If anyone has info on this, please post in the comments.