I'd like to begin by simply saying I do not claim to be a M70 expert, simply a huge fan of this rifle. If I am incorrect on any facts, feel free to correct me. If you'd like to add more, please do!
Besides a full custom rifle, I'd have to call this rifle perhaps my favorite, all time. Especially the original pre '64 Featherweight version. The original M70 started being produced in the very late 30s. It began re-production after WWII and there are some versions/models called transition models, as a few miner alterations were made to the M70 rifle at that time.
Basically the rifle is a close cousin to the M98 Mauser with a few differences. Perhaps the best known is the very famous 3 position safety of the M70. It allows for safe(bolt locked) position, safe (bolt unlocked) position and fire positions. This is by far my favorite type safety ever. Ruger uses a similar system today as well.
Model 70 rifles were originally produced with 24" barrels (magnums had 26"). In around 1953 the Featherweight version was released. It used a 22" slightly lighter contour barrel and aluminum floor plate (and butt plate) system to trim weight. The stock looks all but identical to the standard rifle to my eye, so I doubt any weight was saved there.
Both versions had a simple point pattern checkering that was useful if not particularly handsome. The action on every early M70 (through 1960s) was left matte and the floor plate and barrel in polished blue. Many, many chamberings were made and I'd be a fool to try and mention all here. Some as odd as the .35 Rem and 9mm were produced along with pretty much all standard, popular American cartridges of the day.
In 1964, the rifle was changed some and lost a lot of fans. Biggest changes included pressed vs cut checkering, different bottom metal and the loss (horrors!) of controlled round feeding and full length extractor. Fans were NOT amused at these changes, likely made to compete (at lower production cost) with the then new M700 Remington (1962). The strategy did not work.
The rifles made immediately afterwards are perhaps the least desireable of the M70s but if you want a rifle that is of excellent quality, but simply lacks the panache of a pre '64, buy one! You will not regret it, I promise. They are very nice guns, period. :thumbsup1: My 1966 rifle shoots sub MOA and is a nice smooth handling and functioning rifle. Everyone who handles it, wants to buy it! Not for sale, however. 
The Featherweight model also left post '64 and did not return until the early to mid eighties. These newer Featherweight models are by far my favorites, looks-wise. Simply beautifully designed rifles. The next F/W iteration was the Featherweight "Classic" which brought back the CRF and full length extractor loved so much on the pre '64s!
Winchester Corp has changed hands a few times over the years and a few years back the New Haven plant closed it's doors for good, halting production of both the M94 and M70 Winchester rifles. FN has recently started making new M70 rifles in their S.C. factory and word I have is that they are as well made as ever!
I've owned a bunch of rifles over the years (over 100 big game rifles) and if I could only have one production rifle, it would be a M70. To me, they are simply that nice. If you ever have an opportunity, handle a well kept pre '64 rifle and work the action. It is simply something special! The 1960 Featherweight I now have was supposedly made in the custom shop at Winchester and it is a very good looking and extremely good shooting rifle.
Some pictures here: https://www.biggamehunt.net/galleries/tndeerhunter/classic-rifles
