They must be aware that at any moment the gun could go off while they are working around the muzzle. The flame coming from the bore can easily reach out to 25 feet.
L again Wearing of gloves is very important.
Welding gloves gives the men the best protection, as the following pictures show. A chicken was put in a white cotton glove and one in a welding glove. They were wrapped around a pound of pounder and blownup.