The chances are good that the bolt is having a hard time finding the throat in the strike plate. Be sure the strike plate is secure and is in reasonable alignment with the bolt. You can file the edges of the strike plate a little, and even slightly round the edges of the deadbolt's end. If this doesn't work, you'll probably have to remove the strike plate, fill the screw holes with glue and wood matchsticks, reposition it properly, and re-screw it.

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