Have you had it apart?
Is it hard to lift the entire travel, or just at the start or at the end?
I have my suspicions, but you will need to disassemble the firing pin assembly from the bolt body.
To do this easily, do this, using your shoelaces loop, place it in the rear notch of the cocking piece, pull rearward and turn the bolt body counter clockwise and screw the bolt off the firing pin assembly.
I'm suspecting the pin that attaches the cocking piece to the firing pin is either protruding, bent or a combination of both.
Also check the firing pin spring for debris lodged between coils, machining swarf or a broken spring. If you've had pierced primers, look for the blanked disc inside the bolt body.
Let me know how you get on.
I will give you more instruction if you need to disassemble the firing pin assembly.
Cheers.