-- A gun is worth what it'll sell for, but to help determine it's value, check out Guns International, Guns America for what folks are asking and
www.gunbroker.com to see what people have bid and paid. To position a gun within the parameters of it's potential value, three factors are usually considered:
1. Rarity
2. Originality
3. Condition (NRA Grading System)
With M70's the term "correct" means a lot. If the gun is not in original condition; eg. reblued, refinished, stock cut and pad added, or any non-factory alterations, the gun's rating goes to 'Fair Condition" no matter how fine a shape it's in. Most pre-64 M70's came with a checkered steel buttplate. Around 1959 to 1960 the plastic checkered buttplate began to filter in and by 1961 was pretty much standard. 375's mainly came standard with pads as did Westerners and Alaskans. The 264 Westerner came with a plastic buttplate and was the only caliber featherweight available with a factory recoil pad. No other featherweights were offerred with a pad. Winchester began using the vented pad around 1961 but some solid red Winchester pads were still used. Winchester was famous for "Running Changes". Also, solid red pads can be factory correct on a special order gun if backed up with paperwork.
Pre-war models are worth a premium over post war, and Super Grades are worth about a 100% premium over Standard Grades.
Winchester made around 581,400 M70's between 1936 and 1963. When Winchester geared up for WWII, they stamped the last receiver around 52,000, continuing after the War ended.
!. Rarity -- caliber and model
2. Originality -- has it been messed with or still original
3. Condition -- NRA website, condition from NIB to Poor.
Some examples of rarity:
30-06 / 208,000 --- 270 / 122,000 --- 243 / 43,600 --- 308 /41,100 --- 300 H&H / 37,100 --- 264 Win Mag / 24,000 - - - 22 Hornet / 20,000 - - - 257 Rbts / 14,600 --- 220 Swift / 20,000 - - - 375 H&H / 14,000 --- 338 / 9,500 --- 300 Win Mag / 5,000 - - - 250-3000 /2750 --- 458 Win Mag / 1550 - - - 7mm / 1,470 --- 300 Sav / 362 - - - etc.
Some of the different models are: Standard Grade - Super Grade - Standard Featherweight - Super Grade Featherweight - Carbine - National Match - Target Grade - Varmint - Westener - Alaskan - Gopher Special - Bull Gun - and Special Order Guns.
Hope this helps you some.