29×191

29x191 refers to a specific type of artillery shell, likely a projectile fired from a naval gun or a heavy howitzer. The designation "29x191" indicates the caliber of the gun in millimeters, which is 29 mm, and the length of the projectile in millimeters, which is 191 mm. This is a relatively small caliber for naval ordnance but could be found on smaller vessels or in specialized roles.

The "x" typically denotes the relationship between the bore diameter and the projectile length. In this case, it signifies a 29 mm bore firing a 191 mm long projectile. The exact type of projectile would depend on its intended use, such as high-explosive, armor-piercing, or perhaps a specialized round like illumination or smoke. The length of the projectile suggests it might be a full-bore shell or potentially a sabot-fired round where a sabot casing is discarded after firing, allowing a smaller projectile to be accelerated to high velocities.

Without further context, it is difficult to pinpoint the exact weapon system or historical period associated with a 29x191 shell. However, such designations are common in military ordnance catalogs and technical manuals. The precise performance characteristics, such as muzzle velocity, range, and penetration capabilities, would be determined by the specific gun it was designed for and the projectile's construction. Researching historical naval artillery or specific artillery pieces might reveal more details about this particular ammunition type.