The Sightmark Laser Boresight is an in-chamber laser boresight designed for firearms chambered in .30-06 Springfield, .270 Winchester and .25-06 Remington. Its brass housing and 632–650 nm visible red laser provide an initial alignment reference for a riflescope, red-dot sight or iron sights before final range verification.

Suitable for use

• Preliminary sight alignment on .30-06 Springfield firearms

• Preliminary sight alignment on .270 Winchester firearms

• Preliminary sight alignment on .25-06 Remington firearms

• Checking a newly installed or replaced riflescope

• Initial adjustment of red-dot and reflex sights

• Checking iron-sight alignment

• Verifying sight settings before visiting the range

• Hunters and target shooters

• Owners of several firearms in the compatible calibres

Why choose the Sightmark SM39003?

• One device is compatible with three calibres

• Fits .30-06, .270 Win and .25-06 chambers

• Installs directly into the firearm’s chamber

• Visible 632–650 nm red laser

• Manufacturer-specified sighting range of 15–100 yards

• Approximately 2-inch laser dot at 100 yards

• Durable brass construction

• Simple on/off end-cap operation

• Approximately one hour of battery life

• Batteries and protective carrying pouch included

• Helps reduce the time and ammunition required for initial sight adjustment

Technical specifications

• Compatible calibres: .30-06 Springfield, .270 Winchester and .25-06 Remington

• Laser type: Visible red laser

• Laser wavelength: 632–650 nm

• Laser output: Less than 5 mW

• Sighting range: 15–100 yd / approximately 14–91 m

• Dot size: 2 in at 100 yd / approximately 51 mm at 91 m

• Power supply: 3 × AG3 batteries

• Battery life: Approximately 1 hour

• Operation: On/off end cap

• Body material: Brass

• Operating temperature: –10 to +50 °C

• Intended use: Preliminary sight alignment

• Ammunition status: Not ammunition or a snap cap

• EAN: 810119010025

Supplied with

• Sightmark SM39003 laser boresight

• 3 × AG3 batteries

• Protective nylon carrying pouch

• User manual

Frequently asked questions

Is one SM39003 boresight compatible with all three calibres?

Yes. Sightmark specifies this model for .30-06 Springfield, .270 Winchester and .25-06 Remington chambers. This does not mean that ammunition for these calibres is interchangeable.

Can this laser boresight provide a final zero?

No. It indicates the approximate direction of the bore and is intended for preliminary sight alignment. The final zero must always be confirmed with suitable ammunition at an authorised shooting range.

Which batteries does the Sightmark SM39003 use?

Sightmark’s model-specific battery guide specifies three AG3 batteries for the SM39003. The batteries should be removed after use to reduce the risk of discharge or leakage.

Is the red laser visible in daylight?

Visibility depends on ambient light, background colour and distance. The red dot is easiest to see indoors, in shade or in reduced light, while its practical range may be shorter in direct sunlight.

When is the Sightmark SM39003 the right choice?

This model is a practical option for shooters who own a firearm chambered in .30-06 Springfield, .270 Winchester or .25-06 Remington and want a compact preliminary alignment tool. Because one device is compatible with all three calibres, it is particularly useful for owners of several suitable hunting rifles.

A universal boresight may be more economical when many unrelated cartridge families need to be checked. The comparable Firefield model is another calibre-specific option. No laser boresight replaces final range verification because the actual point of impact is affected by ammunition, distance and the characteristics of the individual firearm.

Expert recommendation

The Sightmark SM39003 is particularly useful after installing a riflescope, removing and refitting its mounts, or when the sight setting may have shifted. A clearly visible target at approximately 18–27 metres provides a practical reference for the initial check. The firearm should be held securely and pointed in a safe direction.

Always confirm that the firearm is unloaded and remove all live ammunition from the work area before inserting the device. Place the boresight into the chamber carefully, without forcing it or closing the action aggressively. Keep the laser away from eyes, people, animals and reflective surfaces. Remove the boresight before loading the firearm. Take out the batteries for storage and avoid overtightening the battery cap.

One laser boresight for three hunting calibres

The Sightmark SM39003 provides a straightforward way to pre-align the sights of firearms chambered in .30-06 Springfield, .270 Winchester and .25-06 Remington. Its brass construction, three-calibre compatibility and protective carrying pouch make it a practical addition to a hunter’s or target shooter’s equipment.