The 100-yard (simulated 250-yard) sight-in of the Leatherwood M1000 ART Scope. Rifle is the Armalite AR-10 NM.
The 100-yard (simulated 250-yard) sight-in of the Leatherwood M1000 ART Scope. Rifle is the Armalite AR-10 NM.

Editor’s Note: In Part I of this series we looked at the history and concept of the Leatherwood Hi-Lux M1000 ART Scope. In Part II, we’ll discuss setting up and sighting in this unique optic. And in Part III we’ll head out to the big range to see how well it ranges and compensates for shots out to 600 yards.

Setting Up the ART M1000

To test out the Leatherwood ART (Automatic Ranging and Trajectory) M1000 scope, I mounted it on the very excellent Armalite AR-10 NM (National Match) rifle. The ammo was Hornady TAP in .308 Win. (168 gr.). That’s all best quality stuff, so there’s no reason this rig shouldn’t shoot — and shoot well.

Calibrating the cam on the ART M1000 scope to your chosen caliber and load is easy. Simply look up your cartridge in the instructions to determine the code, then loosen and align the calibration ring with the power ring. In my case, I needed a code of 420 for the .308 168 gr. load.
Calibrating the cam on the ART M1000 scope to your chosen caliber and load is easy. Simply look up your cartridge in the instructions to determine the code, then loosen and align the calibration ring with the power ring. In my case, I needed a code of 420 for the .308 168 gr. load.

To mount the scope on the gun, the ART M1000 has two large knurled thumbscrews used to tighten the base — which is actually integrated as one-piece with the scope — onto the Picatinny rail of the rifle.

What I liked about this: It was fast and didn’t require any tools. What I didn’t like: After the first dozen or so shots you need to check and slightly retighten as the fasteners and lock washers settle in. However, the scope does ship with split washers and butterfly wingnuts for a more secure mount.

Having done this, next step is to calibrate the cam to your chosen caliber and load. A table in the instructions makes it easy to find the correct load and indicates the corresponding code.  For the 168 gr. .308 it was #420.

In the accompanying photo you can see how the calibration ring is loosened and rotated to line up with the arrow on the power ring. Simply re-tighten and you’re calibrated.

Later on, when we shoot at distance, we’ll have the option to tweak this cam setting based on an actual flight performance of our load/gun in our environmental conditions.

Sighting in the ART M1000 scope. To estimate a 250-yard zero on a 100-yard range, use the hash mark directly above the center crosshair on the reticle. The trajectory algorithm of this scope is based on a 250-yard zero.
Sighting in the ART M1000 scope. To estimate a 250-yard zero on a 100-yard range, use the hash mark directly above the center crosshair on the reticle. The trajectory algorithm of this scope is based on a 250-yard zero.

Sighting in the ART M1000

Remember that this scope was developed in conjunction with the military during the Vietnam War to provide Army snipers with a fast way to range and shoot targets. Essentially, the power ring—which goes from 2.5X – 10X—is married to the base via a cam.

This “no math” method of ranging targets makes sense in the heat of battle. You simply insert a target of known dimensions (18-inches or 1-meter) into a bracket on the reticle by turning the power ring.

Let’s say you’re mule deer hunting, and have a buck at long range but the distance is unknown. Looking through the reticle, you turn the power ring until the approximate 18-inch chest of that deer fills half the bracket inside the reticle. You can now do two things: Swing the crosshair over to the buck’s chest and shoot, or peek at the power ring to learn the distance (most critical for wind correction).

That means that when the target is at 250 yards or closer, you’ll be on 2.5 power. When the target is 500 yards, you’ll be on 5 power, 700 yards 7X, 800 yards 8X and 1000 yards 10x.

The first shot with the scope landed about six inches right and low. The ¼ MOA clicks on the turret were spot on and quickly brought the subsequent shots into the black. Note that the M1000 scope is designed to be zeroed at 250 yards. Not having that much real estate at the range I was using, the instructions suggest using the top hash mark above the crosshair for a 100-yard sight-in, which should put me on at 250.

If I could change one thing about the scope I’d go with thinner crosshairs. At 100 yards shooting on 2.5 power the width of a crosshair is about 1 MOA. I was able to shoot a 1.75 MOA group at that range, which is about as good as I could do with thick wires.

It should be noted that the scope can be shot in “manual mode” where you unlock the power ring from the cam. In this mode you could shoot with the scope on 10X, which would help with precision. The downside is that you lose the autoranging capability, which is sort of the point of this scope.

Having gotten the Leatherwood ART M1000 scope sighted in and on paper, we’ll next head out to the 600 yard range and try to hit stuff at ranges unknown.