Holosun AEMS Pro X2

The Pro X2 ships already bolted to Holosun's 1.63 inch lower 1/3 pedestal mount, so installation is one fastener: an 11mm hex nut on the underside of the rail that draws the clamping block against the slot. Holosun specifies 50 to 65 inch-pounds, which is 5.6 to 7.3 Nm.

The 11mm wrench in the box is a stamped flat tool that no torque wrench will accept, and the cross bolt protrudes through the middle of the nut face, so a flat blade or a coin cannot seat on it either. An 11mm socket from your own toolbox is the only way to actually measure the spec instead of guessing at it. Clear the firearm and remove the magazine before the optic goes anywhere near it.

The Pro X2 runs a single CR2032 3V lithium cell in a side-loading tray, so the battery changes without breaking the mount or losing zero. One cell ships with the sight, and Holosun rates runtime at up to 50,000 hours with the solar cell carrying part of the load.

Polarity is the step people get wrong: the battery goes into the tray with the POSITIVE side facing DOWN, not up. The tray carries an O-ring seal that is what earns the sight its IPX8 rating, so inspect it on every change.

Elevation lives on the right side of the housing and windage on the left, both slotted for the flat driver end of the included T10 tool. Each click is approximately 0.5 MOA, which works out to 1/2 inch at 100 yards, 1/4 inch at 50 yards, and 1/8 inch at 25 yards. Total travel is 50 MOA from center in each axis.

Turret directions are the opposite of the habit most shooters build on rifle scopes: clockwise on elevation raises point of impact, and clockwise on windage moves point of impact right. Holosun mechanically zeroes the sight at the factory, which sets the turrets to center, not to your rifle. A sample can still come out of the box a long way off, so budget a full session rather than three rounds.

The Multi-Reticle System cycles by button hold, not by menu. Holding the "-" button for three seconds steps the reticle through circle-dot, then dot only, then circle only, in that order, returning to circle-dot on the next cycle. The circle is 65 MOA and the dot is 2 MOA, and the ring subtends roughly 5 feet 5 inches at 100 yards, which makes it a usable range estimator on a torso-sized target.

Shake Awake sleeps the reticle after 10 minutes of no movement by default and wakes it instantly on motion, returning to the last brightness used. That timer is programmable, and one of its four options disables the sleep behavior entirely.

Press either "+" or "-" once to power the sight on; press both together to power it off, which also stops Shake Awake. Holding "+" for three seconds toggles between auto and manual mode, and a single reticle blink confirms the change. The sight remembers the last brightness setting through a power cycle.

Manual mode exposes 12 brightness levels, with settings 1 through 4 night vision compatible and 12 the brightest. Auto mode behaves differently by reticle color. On the red model the sight moves between solar and battery power on its own and the buttons switch between a high and a low level. On green and gold the eight daylight settings run 3 through 10, and pressing a button sets a floor: the sight varies upward from that setting toward 12 as forward light increases, and never below it.

Both lens covers are transparent, and the sight is usable with them closed. Lift the latch and a cover springs open. A reticle reflection seen with the covers closed is the flip glass reflecting, not a fault in the sight, so judge the reticle with the covers open. The front cover comes off with the two screws beneath it using the included T6 Torx tool; the box also contains an anti-reflection front cover, and its springs transfer from the cover you removed into the matching slots on the replacement.