I had some experiment with my vsr-10 today, I have always been annoyed of the little clicks and clanks when moving the bolt handle up and down.
Firstly, get some semi- thick grease, open the bolt from behind, and put grease in there, there is no limit, so put it in there plenty.
Now we are rid of the "clank", to get rid of the clink, you have to have some shrink tubing, put it on the small rod that goes down when cocking, and up after it, making an annoying click. After you have shrinked it on there, you have to file the hole where it goes through to fit because otherwise the shrink tube will be blocking it, then glue it to place.
I will add pictures soon.