I found two brothers who were mustered into this company in St. Joseph in March 1862. They were Henry A. and Andrew Jackson Wilson of Holt County, Missouri. They both deserted on May 14, 1863. Can anyone tell me if anything significant happened to this company on or around this date or where they would have been? Where can I find a summary of what action they may have seen between these dates?

Also, what usually happened to deserters?

Most importantly, I only have the index cards to their service records so far. Where can I find the original service records and what type of information is generally included in them? I assume NARA isn't the place because they were in the State Militia.
I'd appreciate any help anyone might be able to give me.

Richard Wilson