A smart rifle optic based on the U.S. Army's XM157 Next Generation Squad Weapon fire control. Lase a target and the optic works out the bullet drop for the round in your chamber. It moves the aim dot to match, and on a moving target it shows where to lead.

• Laser rangefinder out to 1000 m, as a single lase or a live readout.
• Ballistic computer. Reads the chambered round's real velocity and drag and corrects for uphill and downhill shots. You hold the dot on the target instead of dialling.
• Target tracking. Lock onto a player, infected, animal or vehicle. Brackets follow it, the range updates as it moves, and a lead dot shows where to aim.
• First focal plane reticle at 4x and 8x. One tick is one mrad at both.
• Full HUD: range, holdover, time of flight, compass heading, loaded ammo type and battery.
• Five reticle colours.
• Four versions: tan or black, on a scope rail or a Warsaw (AK) side rail.

Items

All four work the same. Each weighs 1.1 kg, takes a 9V battery and is repaired with an Electronic Repair Kit.

Getting started

1. Attach the optic to your rifle.
2. Attach a 9V battery to the optic.
3. Load the rifle and aim down the sights. The HUD comes on.
4. Put the crosshair on the target and press Y to lase it.
5. Put the green dot on the target and fire.

The optic only draws power while you're looking through it. A full 9V lasts about 15 minutes of scope time. Without a battery, or with a flat one, you get the glass and the reticle but no HUD.

Controls

All keys can be rebound in the game's controls settings, under Demo X157.

The game's normal zoom key switches between 4x and 8x. The zeroing keys do nothing: the optic is fixed at a 100 m zero and moves the aim dot instead.

Modes

B steps through four modes, which combine two settings:

STATIC + LASE → STATIC + LIVE → TRACK + LASE → TRACK + LIVE → back to STATIC + LASE

Leaving TRACK (going from TRACK + LIVE back to STATIC + LASE) drops any lock.

Ranging and the aim dot

1. Put the crosshair on the target and press Y. The HUD shows LAZING for half a second, then the range.
2. The optic works out the drop for that range and moves the aim dot down by that much. Hold the dot on the target and fire.

• The dot is green when it has a firing solution. It's red at the centre of the reticle when there is none yet: nothing has been lased, or the rifle has no round chambered and no loaded magazine.
• Lasing the sky, or anything past 1000 m, misses, and the previous range stays.
• Inside 100 m the drop is 0 and the dot sits on the crosshair.
• The solution uses the round in the chamber, or the next round in the magazine. It reads that round's muzzle velocity and air drag, and the rifle's velocity multiplier, so modded ammo and rifles work too.
• Uphill and downhill shots are corrected with the Improved Rifleman's Rule: drop is worked out from the level distance to the target, not the slant distance.
• The reticle is first focal plane: it grows and shrinks with the zoom, so its mrad ticks match the HOLD readout at 4x and at 8x. Use them to hold over by eye if you prefer.

Tracking

In TRACK mode, lase a player, infected, animal or vehicle to lock onto it.

• Brackets frame the target and follow it, sized to fit it. A deer and a bear get different brackets, and so do a hatchback and a truck.
• The range floats above the brackets and updates as the target moves. The holdover follows it.
• The mode reads TRACK * while a lock is held.
• The lead dot shows where to aim. It allows for the target's speed and the bullet's flight time, plus drop. Put the crosshair on it and fire. It's anchored to the spot you lased, so lase centre mass. On a target standing still it sits at the drop point on that spot.
• While a lock is held, the normal aim dot is hidden. The lead dot replaces it.
• Lasing anything else in TRACK mode just measures range, like STATIC. Lasing a new target moves the lock to it.

Losing the lock

The lock drops when:

• the target dies or despawns.
• you lose sight of it for 2 seconds.
• your weapon is lowered, holstered or swapped for 3 seconds. Cycling the bolt doesn't count, and nor does coming off the scope with the rifle still raised.
• you cycle out of TRACK mode.

When you lose sight of the target, the brackets and range freeze where it was last seen and turn red, and the lead dot disappears. If you see it again within 2 seconds, the brackets jump back onto it and turn white. If not, the lock drops. This lets you hold a lock through brief cover like a fence post, a bush or a gap between buildings.

Lead indicator

J turns the lead dot off and on (on by default). With it off:

• Locking, brackets and the range readout still work.
• The normal aim dot comes back with drop only, as in STATIC mode. You lead by eye. The TOF readout helps.
• The mode readout adds NL, for example TRACK * NL.

Turn it off when you'd rather judge lead yourself, or the dot is in the way.

The HUD

K cycles the reticle colour: white (default), cyan, green, red, amber. Colour is only for visibility. Other players never see your HUD.

Troubleshooting