The parent cartridge on which the 7.92×57mm Mauser is based was adopted by Germany in 1888 as the Patrone 88 or M/88. The M/88 cartridge was loaded with a relatively heavy 14.6 grams (225 gr) round-nosed ball cartridge with a diameter of 8.08 mm (0.318 in) and was designed by the German Gewehr Prüfungskommission (G.P.K.) Rifle Testing Commission.
 
This easy to use and self-contained bore sighting system fits in the chamber of your rifle. It projects a powerful red laser beam down the bore of the rifle for sighting to the point of aim, without firing a shot. 
 
Works with telescopic scopes, holographic red dot sights and standard iron sights. The durable brass housing looks like a cartridge case but actually contains the laser system and batteries. All you need to do is insert the batteries and screw the cap on the housing to turn on the laser, vice-versa remove the batteries to turn the laser off. 
 
Insert the entire laser cartridge into the chamber, gently close the action and aim at a target 20-30 yards away. Adjust the windage and elevation of the scope or sights until the point of aim is zeroed in.
 
This laser bore sighter is designed for 8x57-JS rifle chambers and should not be used in other calibre rifles.
 
Specifications:
Easy and convenient to use.
Solid brass construction.
Laser wavelength: 630-680nm.
Beam power: <5mw.
Sighting range: 10-75yds.
Dot size: 1.5" @ 100yds.
Power Source: Three AG3 Button cell batteries.
Length: 57mm(2.2'').
 
Improves your accuracy and saves money on wasted ammunition!