Jason,
Jeff was correct about the projectile that goes with your case. Your case M114A1 was used exclusively with the M431 HEAT-T projectile.
I'm guessing you don't have an electronic copy (Pdf) of TM 43-0001-28 Artillery ammunition. It lists every case, primer, fuze, etc. that is used on each round of ammunition. That is how I confirmed what it was used on, just looked up the two HEAT rounds used in 90mm and the cases they use.
You might be able to find the manual online by Googling it. If not, send me your email, and I will email it to you. It is the U.S. modern Artillery ammo bible for collectors.
As added notes, your case was made by Norris Industries in Vernon California.
You might encounter cases in the future that have holes machined in them on the case head, where they have imbedded high pressure test sensors to record the pressure in the case when it was fired.