Remington 512 fires when bolt handle closed

I have a 1950's vintage .22 cal Remington 512 (passed from Dad) that sometime fires when the bolt handle is "closed". It doesn't happen all the time; and sometime it drops the firing pin on the back of the bolt without firing the round. About 75% of the time it works as "advertised", but goes off unexpectedly for no "found" reason. I took the rifle to a gunsmith several months ago to have it "relined" and to have the trigger "fixed"; the new liner returned the rifle back to its original accuracy level, but they were unable to fix the "haphazard" and dangerous trigger malfunctions. I can preclude this "unsafe" condition by putting the gun's "safety" on before opening the bolt and "cocking" it. I have looked at all three (3) versions of this Remington (rifle) "rim fire" to include the "clip" and "single shot" versions (this one's a "tube fed" model) and they all are have similar trigger mechanisms, but with different trigger/sear parts listed. Any help will be appreciated! On last resort, I will attempt to purchase a new trigger assembly, if available. Thanks, Kaiser

We recently had one in the shop doing the same thing. A complete dissasemble and clean fixed it. So I'd start there and while you have it apart you can look for worn parts. Something should show up.

This "accidental firing" situation has been a long standing "off and on" problem for this rifle over a span of many years; only, it has gotten worse recently this year when I decided to take it to a gunsmith to have it "fixed". I thoroughly cleaned it before I delivered it to the gunsmith. The gunsmith did not indicate any worn parts, yet he could not fix the problem. Would the problem indicate a bad sear, trigger, or bolt? Thanks for any help.

Check the staked trigger axle screw. If it's too loose it might uncock on closing. It should be just below flush. But could be worn sear/ striker. My dad's 511 and my 511 did the same thing and on a whim I swapped bolts. They both worked after that so I accepted the luck and they still work.
Good luck with yours; they are great .22s.

Mine had a worn trigger but its over 50 years old and all 5 of my boys shot the heck out of it and it was my first rifle so it is well worn.

Thank you for the inputs! Kaiser

Does the bolt come out w/o pulling the trigger? One of the drawbacks to this series of rifles is that the sear is the bolt stop. Vigorous working of the bolt will damage or prematurely wear out the sear. First I would check the screw as suggested by TbG. The bolt should be retracted somewhat gently only to eject the spent case.

Wall-“bingo”, some of the time the bolt will pull completely out. I suppose I have a sear worn beyond repair. If I manually push the trigger forward, it works fine, but cannot be relied on to not drop the firing pin before I pull the trigger. Is it possible I’m also missing a return spring on the trigger? Thanks

A spring might help for a time but when the bolt comes out, it is usually the sign of a bad sear. The old fix was a new bolt but they are getting hard/expensive to find. You may be able to file a little deeper notch in the bolt and /or "sharpen" the trigger to catch better.

Kaiser does the sear look like this one?
https://www.brownells.com/rifle-part...prod10798.aspx