Assembly of 1938 S/42

[mvilla]

I just registered on the forum and maybe this question has been asked here before. I own a numbers matched Luger, 1938 S/42. Occasionally through the years I have disassembled and assembled the gun numerous times to clean and oil, etc. Last night I disassembled it as usual cleaned and oiled, but now I now cannot turn the 'locking bolt'. The bolt won't line up and slides up on the steel spring incased in the frame. I cannot wiggle the locking bolt into place. Anyone have advice for me on how to align the locking bolt? I've cleaned the frame where the bolt goes in using solvent, oil and compress air to blow anything out that could have settled underneath the 'steel spring'. I call it a steel spring because I don't know what its technical name is. All suggestions will be appreciated. Thank you.