Skirmishing with Light Arms 5: Into the Night.

I am going to use Use of A Long-Distance Night Vision Device For Wildlife Studies because although it is a little dated (1992), they are using a 3^rd generation scope with a telephoto lens attached so.  It gives its resolution findings in understandable terminology (can you tell a raccoon is a raccoon at 1200m?) rather than lp/mm which is a little hard to sink ones teeth in.

Now I am sure your first thought is the same as mine.  Boy, they sure have some big raccoons in Mississippi!  They don't comment on people, but you would suspect that they would be somewhere toward the top of the range.

In flitting about the web, the following numbers came up:

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  You could distinguish people at 75 to 100 yards
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  Infrared Laser Illuminator-Red Dot Scope was good from 100 to 500 yards.
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  Night vision cameras are good to around 400 meters.
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  And of course, the above indicates clear species identification from 300 meters to 1700 meters.

Note though that the longer ranges are with some sort of telescoping lenses that will allow precise identification, but within a very limited arc.  You also have some exceptional military thermal imaging systems that will generally cost somewhere in the six-digit $ range.

Some of the modern scopes  ( Eotech comes to mind) will allow you to use their low to no magnification scopes with your regular monocle, rather than a dedicated piece on your scope.

The final summation:

If you have military experience with advance night fighting equipment,  the ability to obtain said equipment, sniper training, and a Barrett, you obviously are going to be the Master of the Knight. 

For those of a more normal disposition, you would have to conclude that if you Generation 3 and you are faced with Generation 1 technology, you would have a significant advantage. 

If you have any generation technology, and add in a relatively inexpensive infrared illuminator, you will have a very large advantage over those with no technology.  You will possibly be able to open up at 200 to 300 meters, and they may not even be able to see the end of their barrel well enough to aim their fire back at you.  Since this is toward the top of the range that competent people can expect to hit anything in daylight, that is perfectly adequate.  

For a thorough examination of the advantage of even early versions of night vision have over those with none, this article about the experiences of the Howell Twp. Police Department in New Jersey is very illustrative.  One example:

Meth Warrant

A subject who was stopped for a traffic violation was discovered to have a quantity of methamphetamine in his possession. He agreed to roll over on his supplier, an outlaw biker who had a string of weapon offenses on his resume.

The dealer operated out of a two-story house in a remote, “very rural” location, which presented a problem in serving a search warrant: the house sat in the middle of a “wide open” field, making it dangerously difficult to approach without being detected.
Capt. Mayfield, who headed the ESU team assigned to hit the place, describes their strategy:

“We figured that waiting until nightfall would be our best chance, but still, getting across the field, a distance of about 100 yards, could be problematic. We took a night-vision scope off of a rifle and used it as a monocular.

“Starting at about 9:30 p.m., two officers surveilled the place for about 90 minutes. They could see people coming in and out of the house, but we never felt our target left and we didn’t see anything threatening.” The scope/monocular continued to be used as the full six-officer unit moved in for the raid.

“We did a two-team entry, one in the front door and one up the rear, outside stairway to the second floor,” Mayfield says. “The operation was a total success. The suspect never knew what hit him. We also got some drugs, several other people, and a couple of guns—all with no officers hurt and no shots fired.”