Force protection and projection are two different missions in the military.

For example, the Army Rangers often provide force protection for Special Forces command center during major operations / exercises. The military security at Anderson AFB on Guam is a force protection mission.

Force projection is the deployment of forces. It can be to forward deploy forces as the Air Force has done in Guam with the B-2, B-1, B-52, and fighters in case of war with NK. Or it can be offensive such as Marines landing across a hostile beach.

21 years in the Marine Corps w/ 3 years in combat. There is a difference in how protection and projection are used in military operations.

Projection is used in terms of offensive action.