You can get a manual from Remington by going to their website
How to take apart Coast to Coast Marlin 22 cal long rifle Model 00550
You will have to take it apart. Each model is different so you will have to find a diagram of the rifle.
don't take down a Winchester model 52, the way they bedded the rifle was a mystery. It may never shoot the same if you take it apart.
Recommend you ask a gunsmith for help and watch
Need to know who made it. Need to know if it is a bolt action, pump, or semi-auto. Does it have a model number on it?
Best to ask a gunsmith for help if you don't have a manual
To take apart the Gecado .25 caliber rifle, you will begin by making sure that the rifle is not loaded. Remove the retaining pin at the base of the barrel and remove the barrel.
You need a copy of the owner's manual for your rifle- trust me- parts of the bolt are tricky. You can get a copy for free from Winchester is you are in the US. The link below will take you to their order form on their website.
Best to ask a gunsmith for help
Start by going to the Henry website, and download the manual for your rifle. They are free.
Best left to a gunsmith
Take it to a gunsmith for verification