I wasted 5 hours of my life writing this guide

It's like Jewelry Store but instead of farming packages I'm playing a $90 version of Kovaaks.

UPDATE

This challenge no longer exists.

"Go play the game, go enjoy it and you will experience progression."

As promised by the Senior Game Economy Designer at Starbreeze, Charlie Czerkawski, the game's progression is tied to the game's fun. So we're going to have fun by standing still in a spot and shooting enemies that run in a straight line for ~2 - 3 hours.

The Challenges in Question

Rewarding a measly 500 IP (Infamy Points), there exist 5 "Reinfeld 900S Long Ranged Kill" combat challenges which require the player to get 400 kills total with the Reinfeld 900S Sniper Rifle while over 50 meters away. While seeming necessarily harmless at first, practice goes to show how limited you are on distance for almost all of the 8 heists that are available on launch.

If players want to obtain these challenges in a reasonable time that does not include using one of the more poor performing weapons on every heist until they eventually get it out of sheer "face-in-to-brick-wall-until-one-gives" tactics, I have found a strategy that has been reasonably successful in obtaining the requisite amount of kills.

(This is evidence of my daring progress towards the challenge(s) which I will update once I have gotten the challenge fully completed.)

i did it

The Weapon (and recommended skill loadout)

The Weapon

This is the Reinfeld 900S. I highly recommend leveling the weapon first (Which can also be done on Dirty Ice)
Despite being the highest damaging primary weapon in the game, it literally falls short due to how distance penalties are calculated for both headshot and damage multipliers. So, even though we can account for multiplier distance penalties by using Long Shot (explained later) we still need our attachments to minimize the damage lost due to range.

The Attachments

Because, at least for the time being, weapon stats have been degraded to a bar that goes up or down due to arbitrary +'s or -'s, I can only recommend these weapon parts anecdotally.

The Fluted Marksman Sight - Only existing high magnification sight that does not reduce scope speed.
Ranged Barrel - Increases damage distance by "an amount"
Extended Mag - Not completely necessary if you want to cut time weapon level grinding, but, at least for me, is the best magazine available for the weapon
Hardwood - This is personal preference, the other barrels work fine
No BE - Most barrel extensions affect targeting speed (bad) while doing little for the weapon

The Skills

tl;dr - Sharpshooter aced with Long Shot and Cutting Shot to reduce multiplier penalties and enable you to one shot shields through their visor. Tank, Extra Plates, and Armor up basic, because there's really no reason not to have this in any build. Mower, Recoil Handling, Ammo Funnel, and Replenish to maintain up-time with the sniper whilst using Edge.

Now, there is an argument to be made for precision shot, to slightly guarantee a collateral or any range kill that is slightly out of break point range, but I have yet to try it and found little difficulty without using it, so that will be left up to preference.

For a little more in-depth

Long Shot
The Critical Damage Multiplier decreases from a 3.0 to a 2.0 at ranges greater than or equal to 50 m. Damage halves at ranges greater than 60 m. Because we will be idling around this range, and to guarantee we get the kill at range, this skill is necessary to minimize how much damage is lost.

Cutting Shot
The Reinfeld 900S has a base armor penetration multiplier of 1.3. Cutting Shot increases a weapon's AP multi by 0.1. Without this very slight increase, the sniper is incapable of one-shotting shield's through his visor. Even if you weren't doing this challenge, I'd recommend running this skill.

Sharp Aced, Ammo Funnel, and Replenish

These skills work in tandem with each other to give and refresh the Edge that enables you to have a bottomless magazine and almost infinite supply of ammo. Stand still while aiming down sights for 1.5 seconds, and you're good to go. Your Edge will refresh on every head-shot, enabling you to stand still and click enemies for as long as you like.

Build Addendum - Sentry Guns

In the absence of friendship, you will have to rely on sentry guns to alleviate the unwanted spawns.

Fortunately for us, they are fairly straightforward. All the skills you need are located in the Engineer tree with the more notable ones being

ENGINEER Aced - Unlock and reduce heat build up of your sentry by 40%
AP TURRET - Gives it armor penetration and be even remotely useful
COOLING SYSTEMS - Increases up-time and survivability
SPIN CYCLE - Covers a wider range of area
DUAL SENTRIES - Further increases the survivability of one sentry by distributing how much damage they take

Dirty Ice Brain Rot

This strategy is done on Dirty Ice

I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement I heard you were back from retirement

The Spot(s) - UPDATED

This area
Has two major spots players can stand where they have complete line of sight of a spawn where cops will come from, at range and in a line.

The places to stand are indicated by the two accumulative review scores for PAYDAY 3.

You will either be standing here...
Or here.

You are able to stand in the middle of the street to try to get kills from both sides, but since the cops run at you, you have less of a window where the enemy is 50 m away. Committing to one side was consistently, at least for me, better in achieving the most amount of kills per session rather than trying to middleman either side.

Once you have chosen a spot, you just wait for the enemies to spawn and line up...










then you click them.










Red hit-marker means you got a kill, yellow either means you did not get the kill or you got a collateral where an enemy did not die. (Thanks fall-off).

UPDATE

I had previously forgotten to mention that I had done this with two other people.

Without the extra help to minimize the impact of spawns, you're likely to be overwhelmed from either the police that spawn at the back fence or the spawns that come from the alternative side that you are not holding.

So, if you have friends to help you tackle this challenge, I recommend one of them stands here...
to work on their own weapon challenges and to prevent those particular spawns from bothering you.

If you lack the resources (friend) to hold the back fence, you can use sentry guns placed near the entrance of the store to kill those particular spawns.

If you have someone defending the back fence and a particular side is bothering you I recommend
these placements for either hotel side or store side respectively.

Disclaimer and Conclusion

As aforementioned, due to the lack of actual weapon stats, and with how relatively new the game is, a lot of this could be misinformation solely due to the lack of information. This spot has worked for me so far, and, while likely not the most optimal spot, it has made this challenge significantly easier to farm than it would otherwise be.

That being said, I am open to editing this guide to add or clarify based on new information. This challenge and the challenge system in general is a mockery of progression and yet I'm addicted to it because I like when the number goes up. Hopefully this guide successfully helps you with your number.

**Credit to ModWorkshop user Candy and their Old Ahh Contractors mod for the old Butcher image. You can find the mod here[modworkshop.net].

Also, if anyone mentions the Road Rage spot again I will be making another update to explain to people the importance of time management.

[Gabe!!]

this is worse than the burning of the library of alexandria. this is the library of alexandria burning of payday 3.

[MrMountainMan]

what happen

[Shadic]

A quick note I can give you, if you go onto normal mode and wait for an FBI van; you can actually sit on the roof of Gold & Sharke and constantly shoot down the snipers; they respawn almost instantly depending how long the vans been up. Easiest way i got it done

[Family Guy Burger King German]

i heard you were back from retirement, good

[Gold Guy]

i heard you were back from retirement, good

[Spicy]

i heard you were back from retirement, good

[bog business]

i heard you were back from retirement, good

[Felixinius]

God, your guide is funny AND informative, 10/10 + award you deserve it bro thank you very much my friend

[Rya]

Road rage is a way better heist for this.

[Rya]

The problem with sentry gun is they require to be constantly pick up and back down and are pretty effective at killing stuff before you do. So you'll progress lot slower overall on challenge.