Problem with Black Ops?

Every now and then I manage to make a sweet enough kill I insist on making a clip out of it. Here is my problem.....it seems recently only half or less of my matches are saved. The "recently played games" save your past 100 games. I dont know if it is a memory problem or what. Is there a way to clear recently played games? is this even the issue? If i didnt make sense to explain my issue again...exp I played a match 10 min. long but only 4 mins were saved and veiwable.... ??????? any help would be appreciated