Okay. I found the image on Fold3. I think there is one slight mistake in the transcription. The one that says MsR is probably just MR. I am pretty sure the "R" stands for "Regiment" in all instances. The "J" is joined, "M" is missing, "D" may be discharged or perhaps detached, "R" may be recruit. I've read a lot of these types of documents, but they were Civil War era, but basically, these notes are the soldier's movements.
Recruited to Regiment March 1814 - Discharged or Detached Regiment Captain Isaac Carter's Co February 16, Joined Regiment February 28, Missing Regiment April 30, & Missing Regiment Plattsburgh, June 28/15, absent, sick at Portland since June 28/15 - Discharged or Detached Regiment Captain John Merrill's Detachment February 16/15, Present- Discharged at Portland, March 31/15, term expired - See pension case.
You have to remember that these records were originally on a number of separate cards. That is why some of these notates seem to repeat, like when he was sick. Also, each movement needed an officer to issue the order, hence Captain so-and-so.