I am going to say any accuracy difference between the M70 and M700 is unproven. Bud of mine shot this with a M70:
and this:
The M70 was a popular Across the Course rifle for several reasons.
It has a slick and smooth action. It was very reliable, about the only thing that wore out was the extractor on the push feed versions and the cocking piece nose. If you feed the M70 from the magazine, the claw extractor will last, maybe forever. If you drop a round in the chamber and make it snap over the rim, it will break in time. Just as what will happen to the Ruger claw extractor, especially the early 70's Rugers which the claw extractor always snapped over the cartridge rim. Just search the web, you will find a lot of Ruger M77 owners, guys with the 70s versions, looking for a replacement extractor because their extractor broke. .
Don't doubt for a second that extractors and cocking piece noses dot break on M700 either.The M700 was also common on the firing line as an across the course rifle, its most common failure was its extractor. The push feed Winchester, its extractor will wear out, cases will fall off in the loading port during extraction. Winchester M70 push feed extractors are easy to replace, but finding which extractor blade to use is difficult because there are a bunch of different Winchester extractor blades.
The M70 was very reliable on feed and extraction and has a very easy bolt life. In terms of accuracy, you won't see a difference in a hand held rifle.
Here are some fuzzy pictures of one of the last Win 70 actions made at Hartford:
Integral magazine box
detachable magazine box
Winchester widened the left side of the cocking piece shroud sometime in the USAR period, making it a gas block. Gas traveling down the left side of the action rail is blocked by this shroud. Pre 64's and most push feeds don't have this. Roy Dunlop used to make this modification on customer's M70's, it should have been there from the beginning.
As towards action strength and safety. If your number one desire is to blow up your rifle and yourself, the M70 does not have the "three rings of steel" that the Rem M700 has.The M70 has a cone breech, part of the cartridge head sticks out, nothing surrounding the case head, it is just sticking out to the bolt head.
This is not bad, as long as you are not trying to blow up your rifle. If you do have a gas release in a M70, more gas will come out of the action than a M700 because the shrouded bolt head of the M700, goes into the back of the barrel, and that shroud will expand under very high pressure, preventing gas release. It ruins the bolt, but it saves your face. I have always wondered just what action this cartridge was fired in:
Pictures from:
Building a custom Remington 700 hunting rifle,
https://rifleshooter.com/2015/10/ho...r-truing-and-external-bolt-stop-installation/
This breeching also makes the M700 a little more dirt sensitive, but if you want to blow your gun up, the M700 bolt face and barrel hood will make it much more difficult, and will protect you better.
I prefer the M70, it is and was a classic action, and when I could buy a rifle in the caliber I wanted, I preferred to have that rifle as a M70 (or a M98!). There is nothing wrong with the M700, it is a very safe and strong action, and I have several of them.