Which common stoppage with the M4A1 is characterized by a double feed?

A common stoppage with the M4A1 characterized by a double feed occurs when two rounds are fed into the chamber simultaneously, preventing the bolt from closing properly. This can happen due to issues with the magazine or the ammunition. To clear a double feed, the shooter typically needs to perform a sequence of remedial actions, including locking the bolt to the rear, removing the magazine, and clearing the chamber before reloading. Proper maintenance and using quality magazines can help prevent this issue.