Bought a Winchester Model 70 from 1968 (30-06. Nice looking rifle but can't get the safety to work. I've swapped out a firing pin, thought the cocking piece was off but the same problem. Seems it needs about 1/6" more room for the firing pin to come back for the safety to engage. Trigger and sear look fine, so I'm thinking it's the cocking piece.
I've played with Mauser for years but never a Winchester
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Haven't had one apart in years. Needing to come back 1/6" more is a lot. I think the lever cams the pin back a little as it locks. So perhaps the lever is worn and/or pin is worn at that engagement surface plus the sear might not be holding the pin back far enough to start with. That's where I'd start looking.