I do not know where you can get a manual, but I know a little about the ultra rifles. They were made in the 70's to compete with the high-end rifles of that time. The barrels were Douglas premium air gauged match grade. The stocks were a Fajen "aristocrat" the checkering was done in-house by hand by 2 ladies that worked there. I had one in a bolt gun in the early 90's I let get away, it was 308 with a Sako action. I now have 2, a model 700 in 22-250 with an FN action and a very rare model 301 full stock with FN action in a 243. They have all been stone cold tack drivers. the bolt guns had either a FN or Sako action. I think the semi-autos are a great gun as well.
I bet yours is nice! and I bet it will shoot good!