Take an AKM, an AR, a Sig 556, and a SCAR, field strip them all, throw the parts together in a bucket, shake it a bit. Fastest to assemble a gun and shoot it wins.
Field strip an AR and put it in a box covered with a blanket. Shooting competition starts by assembling by feel only.
Make 4 shooting stations, each out to 200 yards. Put them on a 2 mile course. Score is half shooting, half run time.