St. Brigid wrote:
What are the differences, if any?
Traditionally a Sacramentary has only the priest's proper parts, whereas a Missal contained the entire Mass. Modern Sacramentaries usually have 1) the Ordinary, 2) Rubrics 3) The Collect (opening prayer), prayer over the gifts, and the Post-communion (concluding prayer) 4) the Preface and Canon
The readings, as well as the Introit (Entrance Antiphon), Gradual or responsorial psalm, Offertory antiphone, communion antiphon are not included.
In a Missal, all of these are included. Missals begin when priests began to say Masses without other sacred ministers and a choirs. Hence having all in one book was convenient. Up till the early Middle Ages you had an Antiphonary with antiphons, for the choir, a Graduale, a Sacramentary, an Ordo, an Evangelistarum (Book of Gospels), an Epistolarum (book of other biblical reading), or essentially a book for each distinct minister. Some of these still exist (such as the Graduale for the schola, or a Book of Gospels for the deacon), etc