What is Shakespeare trying to do in the beginning of act 5, scene 2, where Margaret and Benedick seem to have an odd conversation?
It seems like they flirt with one another, especially in a way that Benedick would with Beatrice.
The play is all about wit, and Benedick enjoys proving just how witty he is as does Margaret in this scene. And so, this is “normal” conversation for Benedick with a woman, yet he is flirting with her to some extent as well; using their own language, they are “fencing” with each other (playfully). Your question implies you find the sexual meaning in “come over” which first Benedick and then Margaret uses, and this is a fine example of Shakespearean bawdiness. “Give us the swords,” says Margaret, “we have bucklets of our own” (5.2.19) is another way for her to flirt with Benedick, show off her own wit, and to extend the gendered-based themes of the play concerning love and friendship