duke: Now that you've bought the gun I hope you bought a brass cleaning jag for it. This is a brass plug with several grooves in it. It screws onto the ramrod tip or a cleaning rod. They come in several different sizes with each one designed for use with only one caliber. If you gun is a .45 caliber gun, get a .45 caliber cleaning jag.
You will also need some cleaning patches for a .45 caliber gun or just rip up some patches about 1 1/2 X 1 1/2 square out of some old underware.
Now, lightly lubricate the material with some light weight oil like olive oil and push the patch on the jag down the bore.
Pay special attention to the amount of force it takes to keep the rod moving down the bore.
This force should be fairly constant all the way down to the breech plug.
If the rod suddenly becomes much easier to push and then suddenly returns to the previous pressure the barrel has been "ringed" or bulged by the previous owner.
If this is the case, immediately return the gun to the store and ask for your money back. Tell them you have not shot it and simply inspected it and found that the barrel was bulged.
A gun with a bulged barrel will never be able to shoot accurately and it may be unsafe to shoot.
If the pressure on the cleaning rod is constant for the full length of the barrel, welcome to the world of Muzzleloading. I know you are going to enjoy it.