achievementsdiablo-3diablo-3-wizard
Two Wizard Challenge achievements deal with projectiles: Time Takes Its Toll (slow 20 with one Slow Time) and A Forceful Rebuke (reflect 8 with one Wave of Force).
It seems like getting both with the help of the same friendly demons would be pretty easy, but I can't find any that are willing to shoot me that much; gangs are either too small or fire too slowly. Where's a good place to get shot?
In general, there are XP rewards for a certain number of kills with each weapon and there are attachment rewards for a certain number of kills. Attachment rewards are only for primary weapons. Listed below (from this page) are the XP rewards and the attachment reward levels:
XP Rewards:
Certified: 5 Kills - 250 XP
Novice: 15 Kills – 300 XP
Adept: 25 Kills – 500 XP
Specialist: 50 Kills - 1000 XP
Marksman: 75 Kills – 2000 XP
Veteran: 100 Kills - 2000 XP
Sharpshooter: 150 Kills – 3000 XP
Expert: 200 Kills – 5000 XP
Attachments:
Holo Scope: 5 kills
Shotgun: 15 kills
Silencer: 25 kills
Red Dot Sight: 50 kills
Grenade Launcher: 75 kills
ACOG Scope: 100 kills
Airburst Launcher: 150 kills
EMP Launcher: 200 kills
I found the report on a dead body named Wortham Villager Corpse, he was very well marked and appears to be a non-random encounter. It was just prior to getting to Leoric's palace as @Alok mentioned, in the Northern Highlands.
The Villager’s Journal spawns in a Old Keepsake Box at the Old Ruins, it was previously reported in The Lyceum a random dungeon whose location is discussed in this thread. It was unobtainable prior to patch 1.0.3, which led to most of the confusion around it but it is now dropping again.
Best Answer
I got both of these achievements in Act II. The desert is full of wasps that shoot littler wasps, and these littler wasps count as projectiles.
Simply find a group of wasps, cast Slow Time, and stand in the center. Since each wasp fires volleys of 4, you should get the "slow 20 projectiles" in a matter of seconds. Afterwards, simply use wave of force to send them all flying for the second one.