I disagree that the clip should fit snug i have been working on auto trans since 1966 and have never seen a circlip fit tight in the grove. it should go in w/o drag and clamp tight at the bottom of the grove.
example if it went in tight when it was hammered it would tend to open up and stay that way until it moved out of position.
when i check one i will put a little pressure to open the clip and make sure that it turns free in the grove.
of coarse a little bigger and stronger clip would be a plus that way they can straighten the grove.