Savage (Like all gun makers.) has had good and bad time throughout their years. The first Savage produced in 1958 was called the 110 because that is what they cost. The gun doesn't resemble the newer savages by much, as the first years of production showed the most changes. In around the late 1960's to early 1970 Savage made a bunch of changes to the 110 rifle. The changes was in the bolt head design, and trigger mainly, with some other stuff. The newer rifles made in the early 70' until the mid 80's was some of the best machined rifles made. (Rivaling the new stuff.) In the mid 1980's Savage got into financial troubles (Much like other firearms makers.) and attempted to cheapen things up. These rifles showed some lower grade workmanship. It was the mid 90s when underwent new management and the products was brought up to the level they was before. From the early 1970's to this point there was little change in the design of the rifle. There was some bad ideal changes that was attempted in this time, such as casting receivers, soldering the scope bases on rifles and so on, that produced some undesirable rifles during this time.
With the change over of management, Savage developed some new ideas. This was the time that the new "true" short action guns (2nd gen short action.) started out, and other improvement was made. The new short action has a two digit number designation. It was around 2000 when Savage introduced the accu-trigger fixing the Achilles heal of the Savage 110 design the heavy trigger. They also stopped facing of the back of the receiver, and left the action round. The actions was faced off by hand and all most all was never truly straight, and it was an added step that made no since. There was some other refinements such as slight changes making the sears 1 piece, smaller firing pin, and other little small things. Still there was little major change in the design from the guns that came out in the early 1970s to this point.
Latter on in the mid to late 2000 Savage bought new machining and used them to make the newer actions on. It was around this time Savage introduced the precision target action, and changed the magazine system over from the staggered feed to the center feed system. (3rd gen short action years.)It was due to this change over in magazine formats that caused the action screw spacing change in the short actions only. Savage tried some new ideas, such as streamlining the guns appearance with the smooth barrel nut, bottom bolt release and so forth. Besides these changes the guns are fairly much the same design as the guns from the early 1970 until now. It was a couple of years ago Savage changed management again, and is now owed by ATK, and we will see what the future holds.
The thing is the gun has made little design changes since the early 1970's and most parts will interchange. The accu-trigger guns have a different machining process than that of the other guns, and the triggers should not be swapped. The thing is many had a opinion that Savage was junk, and they changed their opinion when the improvement came about in the accu-trigger years. From my experience, I can say that the Savage made in the early 1970 up to present day, all have the same accuracy potential. Savage has been known for years for their "Out of box accuracy."
So with that said the late 1970's to mid 1980s guns are not as well made, but they problems are still able to be rectified. Just avoid the cast receiver, the actions where the scope bases are soldered on to the actions, and the first generation short actions. 4.552 bolt spacing. (1959-88 also know as the "J " actions, as many of them had a j suffix to the serial number. The 1st gen short actions are fine built but they utilize a different bolt length, and action screw spacing than other 110's, and they can be a pin to get parts for. Hope this helps out.
