Final answer:
The MK9 Spotting Rifle, associated with the M40 Recoilless Rifle, weighs approximately 4.5 pounds or 2.04 kilograms, vital for the mobility and endurance of military personnel.
Step-by-step explanation:
The MK9 Spotting Rifle is not a common topic within educational materials, but it is a component used to help aim the larger M40 Recoilless Rifle, primarily used by military forces. The MK9 is known for its role in improving the accuracy of the M40 by firing a tracer round that helps the shooter adjust their aim before firing the main weapon. The weight of the MK9 Spotting Rifle itself is approximately 4.5 pounds (2.04 kg). It is important to understand that the weight of military equipment can be critical for the personnel who must carry it, as it directly affects their mobility and endurance in the field.