There is a "how-to" video of the takedown on YouTube http://www.youtube.com/watch?v=hx36LUD5OTo I was just given a Model 97 and was all excited since I thought the side port loading was very cool since I was a kid. I was looking forward to disassembling and cleaning it as it had not been touched in 25 years. I got stumped pretty quick. I'm going to check the Winchester site (www.winchester.com) to see what they know. Google search has a reproduction of the owner's manual for $5.00. Might be cheaper than breaking something. :o) So far....
Detach the barrel from the stock by means of a screw on the bottom of the forestock. The trigger and an unsophisticated pinned sear release lever arrangement remain attached to the stock. The trigger release is part of the the receiver and has a very fine screw to adjust the trigger pull on the sear. It is independent of the trigger itself.
First off, most of the barrel-receiver assembly looks machined. The barrel is swaged into the receiver and there is an index mark opposite the proof mark (for alignment?). There is no indication that the barrel can be removed, but I didn't force the issue beyond a concerted twist with my bare hands. The action slides rather loosely within the receiver. There is a noticeable difference in the feel of the travel when the safety is changed from 'S'afe to 'F'ire, but the detente that is felt does not lock the action open, though it feels like it should. The curved thumb lever has some rotational and lateral 'wiggle room' but nothing indicated that it was removable. The left side of the receiver contains a very stiff-springed button far to the rear which is inlet. The button is offset from the center of the inlet and can be depressed inwardly, but not very far. It does not engage anything I could feel and has no difference in travel or resistance regardless of the position of the action. I tried it in various combinations of the action with safety on and off. No luck. I have not tried it while depressing the trigger release. The rear of the receiver holds a circular plug at the back end (that I thought I could move, but only very slightly) that might be removeable. If it is removeable, the fit of the plug is of a much finer tolerance than the rest of the rifle seems designed to. So to overcome the apparent lack of a catch to hold the action open for cleaning, I simply cut a section off the end of a wooden paint stirring stick and inserted it in the ejection port! From the wear (damage?) to the breech locking mechanism, it looks like others tried a screwdriver.... I'm sure there's a trick to it, or somke kind of combination and when I get my answer from either trial-and error, book or manufacturer I'll update this narrative.
http://www.swishercs.com/winchester/
Your winchester model 74 was produced by winchester in 1949.
Your Winchester model 74 was made by winchester in 1950.
Your Winchester model 74 was made by Winchester in 1951.
Your Winchester model 74 was made in 1954.
your Winchester model 74 was made in 1940.
Your Winchester model 74 was made by Winchester in 1948.
Watch this video.
Your winchester model 74 was made by winchester in the second full year of production which was 1940.
your Winchester model 74 was made in 1952.
Best left to a gunsmith
Your Winchester model 74 was made by Winchester in the year 1949,with the serial number that you provided.