Cartridge 5.56mm, tracer, M856 should not be used in the M16A1 except under emergency conditions at targets less than how many meters in distance?

The appropriate distance at which cartridge 5.56mm, tracer, M856 can be used in the M16A1 under emergency conditions is 90 meters. This specific limitation is important because tracer rounds can produce a bright visible path of fire, which can lead to undesired effects in terms of both target visibility and potential collateral damage.

Using tracer rounds beyond this recommended distance may compromise accuracy and effectiveness due to various factors, including the performance characteristics of the M16A1 and the behavior of the tracer round itself. Tracer rounds tend to have a distinctive trajectory that can vary, especially at longer ranges.

The choice of 90 meters strikes a balance between maintaining operational effectiveness and minimizing risks associated with using this type of ammunition in a weapon not originally designed to accommodate it. The guidelines regarding the use of tracer ammunition in the M16A1 are informed by safety protocols and the need to ensure operational integrity.