Winchester SX3

My buddy has a winchester SX3. It is a light recoiling gun. Cycles any shell. From doves to geese. Today we had a nice little sporty shoot on the river. My gun and his were working just fine. We seen some geese on a sand bar. Put goose loads in. The shell was a Kent Fasteel 3 1/2    1 3/8oz   BB  1550fps. We got up to the geese, and we shot 3. We had a cripple witch is expected when shooting them long range. He went to finish the job, and his gun went click. He pulled the bolt back ejecting the shell. He put it back in, and it went click again. We don't know if it was the shell or gun.