The creeking and cracking your hearing is Remingtons wonderful spring dragging on the inside of the bolt body. Years ago Remington tried to lighten their firing pins to reduce lock time, so they reduced the diameter of the pin under the spring. The problem is they didn't reduce the I.D diameter of the spring. When the spring is put in compression it kinks. What you get is a spring that drags and now has a slower lock time than before. You can replace the firing pin and spring with a aftermarket one with a proper fit or for a couple bucks more replace the entire fire control.
To take the fire control out you can clamp the cocking piece in a vise like Larry did or you can get the proper tool and remove it safely. Here's the tool you need to remove a fire control. Once you remove the fire control you'll see what I mean about the spring being kinked.