Your question answers itself, "muzzle loader". You load it from the muzzle.
Actually, that's incorrect. They use the term "muzzle loader" improperly. It's a bolt action black powder rifle. The powder is pre-pressed into slugs that you load into the chamber, along with wadding and a bullet. I would guess you could load it down the muzzle, but it's faster and easier to buy the slugs and load that way.
If your Stevens is a bolt action, it is NOT a visible loader. If it has any part (perhaps the barrel) that is marked as a visible loader, that part has been replaced.
50-150 USD or so
You need to read the owner's manual. This is covered on page 15. Below is a link to the CVA website, and owner's manual for bolt action muzzle loaders. Look for CVA MANUAL below.
Bolt
The Garand rifle is a semiauto, not a bolt action. Do you have a Model 1903A3 bolt action? A Model 1917 bolt action?
A model 1904 is a single shot bolt action rifle.
It is a bolt action rifle.
Book of Bolt Action Rifles should help
A bolt action WHAT? Not enough information to answer.
Bolt action. A few are Fortner (straight pull) bolt actions.
No.
a old ww2 bolt action sniper/combat rifle Springfield made many types of bolt action rifles over a century or so