I bought my first M70 in 25 or so years and at the range I thoughtlessly fed a cartridge as I would on a push feed and it went in just fine. Did Winchester change the extractor size or shape to allow this without breaking the extractor?

They changed the shape of the extractor. Although, some snap over the rim easier than others!

They're supposed to do that... But like McCray sez, some are a bit harder to 'snap over' the rim than others.. If it's too harsh, the extractor needs a bit of TLC in refitting..

When was this change made? In New Haven, Carolina, or Portugal?

Even the Pre '64 extractors would snap over, correct?
And in general, it is less wearing on the extractor to control feed from the magazine, correct?

Correct

Thanks GunDoc7. I always thought the original M 70s had to be loaded from the magazine. That must be Mauser 98s I was thinking of.

^^^^^^^
You're welcome. As noted, I do think it is less wearing on the extractor to load from the magazine.

I believe the Mauser 98 as originally designed had to be loaded from the magazine. But I think many were altered to "snap over", and I believe many commercial versions of the Mauser will snap over. It seems to be a trade off between the most reliable, robust extraction vs. the ability to drop one in and close the bolt if you are in a real hurry. Most seem to take the second choice.

Correct..