What is the free length for the action spring on the M4 carbine for a failure to chamber malfunction?

The correct answer reflects the standard specification for the action spring length on the M4 carbine, particularly regarding its role in addressing chambering malfunctions. The free length of 10 1/16 inches to 11 1/4 inches ensures that the action spring has the proper tension and capacity to effectively drive the bolt carrier group forward. This is critical for facilitating proper feeding and chambering of cartridges, which is essential for reliable firearm function.

Choosing the appropriate length is crucial, as a spring that is too short may not provide sufficient force to drive the bolt into battery, leading to malfunctions such as failure to chamber. Conversely, a spring that is excessively long could cause issues with bolt movement and may lead to improper cycling of the weapon. Therefore, the specified range for the M4 carbine's action spring is vital for maintaining operational integrity and ensuring consistent performance during training and combat scenarios.