Good morning to you and a warm welcome. And thank you Colin for throwing out some info to get him started. Wonderful.
As I explain to all my "newbies", in the introduction membership email (and at the top of the main page on the forum), please see my help section in our Research section. It provides all the necessary info to help get you started in regards to discharge documents, etc. Here's the referral link. Let me know if you have any immediate questions regarding how to get the data. :-) Many new peeps have found this helpful. :-)
Also please do an initial search on the forum and main site - The search button on the forum is located at the upper right corner. Type in "401st" (if you haven't done so already) and it will bring up a ton of info on this unit. :-)
I look forward to talking with you about your grandfather.