General Pension InfoTo simplify the process for clients wanting a pension file, I created a web page with additional information and links. Although I no longer offer this service, I left the page up for those who used it as a reference. You can find it, here. This page includes links to the different online indexes and a little information about the differences.
C and XC InformationAdditionally, there is a link to a 2010 NARA blog (NARAtions) post about C and XC pensions. This is a really useful article to help you understand C and XC pensions. However, it is from 2010, and there is at least one update to it.
A New Home for XC PensionsThe Fall 2015 NARA Researcher News has an article about veteran claim files (including "pensions") transferred from the V.A. to the National Archives St. Louis. Since the newsletter is a pdf, the link will just open the full newsletter. You can click on the title of the article in the table of contents, and you'll be taken straight there, though (it starts on page 7 so click the title next to "7").
C Pensions in LimboThe article is pretty straight forward, but I do want to add a little personal experience. I have a "C" Civil War file that is not at NARA that I have been trying to get for years. I contacted the National Archives St. Louis after the article came out and they were able to confirm that it is still being held by the V.A. The article states files went from a "C" file to "XC" on the claimant's death. This Civil War veteran is clearly dead, but he still has a "C" file. The article also says "XC" files were transferred. You would think (logically) that all Civil War files would have been transferred by now, but it does appear it is literally "XC" files that were transferred. I wasn't sure if the article said "XC" instead of writing out "C and XC." This makes sense if you think from a filing point of view. The pensions are purely numerical. No effort has been made to separate "C" files from earlier wars so that will have to happen before they will be transferred.
If you need a "C" Civil War pension not held at NARA I, you still have to request it from the V.A. for now.
Links from this PostPension page from J.P. Dondero Genealogy
2010 X & XC Pension post from NARAtions
2015 Fall Researcher News with Article on Transferred XC Pensions