Sightmark Laser Boresighter Cartridge, 12 Gauge

The Sightmark 12 gauge laser cartridge is a laser boresighter shaped like a shotgun cartridge. You insert it in the chamber like a normal cartridge, and a red laser (632–650 nm) shines out through the barrel and shows exactly where the barrel is pointing. It is powered by three AG3 button cell batteries, which are included along with a storage case.

Its main use is rough zeroing: if you mount a red dot or riflescope on a shotgun – e.g. for slug shooting – you can adjust the sight onto the laser dot on a target before you head to the range. That saves both cartridges and time. The cartridge can also be used for visual mounting practice, where you practise bringing the gun up and checking that the barrel points where you are looking – but you must not pull the trigger, as the firing pin can damage the cartridge.

What you get with the Sightmark 12 gauge laser cartridge

The laser cartridge is a simple tool for bringing sight and barrel into line:

• Sits in the chamber: Because the cartridge sits in the chamber, the laser follows the barrel's axis directly. A muzzle-mounted boresighter has to be centred in the muzzle and can sit off-axis, especially with chokes.
• Red laser 632–650 nm: The red dot is clearly visible on a target indoors and at the short distances where rough zeroing is typically done.
• Removed like an empty case: When you are done, you open the gun and take the cartridge out like an empty case. There is nothing fitted in the muzzle that you could forget to remove before shooting.
• 3 × AG3 batteries included: The batteries are included, so the cartridge is ready to use. AG3 is a common button cell that is easy to get hold of.
• Compact with case: The cartridge takes up no more space than a normal shotgun cartridge and lives in its own case in your shooting bag.

Maintenance and safety

• Never pull the trigger: The firing pin can damage the laser cartridge. Only use it for zeroing and visual practice.
• Check that the gun is empty: Check chamber and magazine for live cartridges before inserting the laser cartridge – and never store the laser cartridge with live ammunition, so they cannot be mixed up.
• Never look into the laser: Never point the laser at eyes, people or animals, and do not look down the barrel while the cartridge is switched on.
• Batteries: Remove the batteries if the cartridge will not be used for a long time, so they don't leak.