I just bought a "like new in box" .25-06 Ruger M77. The date of manufacture is Oct. 1985. Recently, I took it to the range, to see how it shoots, however I found that it would not chamber a round. This was Federal Premium factory ammo in .25-06. The bolt will come all the way forward, but will not cam down. The only thing I did to this rifle, was to disassemble the bolt for polishing. I took off the extractor, but did not remove the ejector, as the spring is very strong, and I do not have a tool for that. My question is, could I have reassembled the bolt incorrectly? It looks proper to me. The other question is, Could the previous owner have had the action 'trued' and rethreaded the barrel without ever having reset the headspace? FYI: When I reassembled the bolt, I threaded it all the way in, then removed my strain relief, (temporary pin) thencounterclockwise till the little lug seated in it's notch. "Ridge"