I just finished this up today, and the Forerunner Destroyer Commendation along with it. I don’t really like the Vanguard armor since it’s got a big Eff-Me Light on the front of it, but if you’re a completionist, you’ll want it anyway, eh?
Well, I’ll tell you what, man. I’m the type of person where when I want something, I’ll grind the crap out of it for as long as it takes. I make as many methods as I can to do things as easily and quickly as possible. And you want to know the truth?
There is no shortcut to this.
Episode Five, Chapter One has the most Crawler Snipers in a single level, to be certain. In fact, I think it has the most of everything in that one level, and it’s a surefire way to blow away loads of Crawlers, Knights, and Watchers of all sorts… If you still need them all. Once you hit the point where all you need is those pesky Snipers-- And rest assured, those will be the last thing you need to kill-- then you’ll come to a crossroads.
You have two options.
You can continue playing E5-C1, raking in somewhere between five and fifteen Crawler Snipers per play, usually on the higher end of that spectrum. But you’ll soon find that this level is really long, and you’re wasting a lot of your time by having to kill hordes of angry Beetle-Borgs just to kill that handful of Snipers.
Or… You can settle in for the long haul.
The option I decided was more efficient, but woefully boring, was to play Episode One, Chapter Three. Use a Designated Marksman Rifle, Battle Rifle, Carbine, or Light Rifle. Make sure that’s in your first loadout for sake of ease. Spawn, turn right, scope in. There’s a Crawler Sniper right there, guaranteed. Fire. Headshot. Pause. Restart mission. Select precision weapon. Spawn. Turn. Fire. Repeat.
I went with the second option because it’s quicker. You don’t end up wasting your time killing loads of other enemies you have no interest in anymore, worrying about whether or not the things are even spawning, defending a glorified antenna for what feels like hours even if it’s just a few minutes. Using the Restart Level option is absolutely brutal, but it’s more effective.
There is no right answer, but I hope this helps you.