Remington 550-1 Issue(s)

Does anyone have any personal- experience/ knowledge with the
Rem.550-1 precautions,or concerns with adjusting or turning the screws&springs under the bolt, near the barrel muzzle? I simply tighten and loosen these screws, then the bolt would not open; then after getting the bolt opened, I tighten the screws again and the trigger would not function, nor could I hear the little when the firing pin was release. What happened and what function does these screws have in common other than, I apparently upset my little 550-1 so now it will not fire. Help!! Thanks for any information.