For anyone unfamiliar, barrel obstructions can be very dangerous as they can result in unsafe pressures when firing.
Here a soldier has put condoms on the ends of these machine gun barrels to prevent sand and dust from entering. Presumably before riding in a convoy along a dirt road.
It’s a time-honored tradition: https://medium.com/war-is-boring/the-combat-history-of-the-condom-46ad46a320df