line up the target on the top of the front sight while sighting the front sight through the rear peep sight.
Go to Remington's web site and request a manaual
Remington's web site has a section with history on each of its products.
Contact Remington on their web site. Your question is impossible to answer without the caliber of the rifle
Go to Remington's web site. They have a list of repair centers.
Best left to a gunsmith
Remington does not show a 870 rifle on their web site. Do you mean the 870 Shotgun? the Remington 870 is one of the most popular shotguns in the us. this shotgun ranges from $300 for the basic model to $1000 for the fancy Wingmaster edition
You can request a owner's manual for free at Remington's web site.
Try Remington's web site. Go to remington.com and order one, they are free for most guns.
Serials are no unique, check the Remington Society site for the barrel code info: http://remingtonsociety.com/rsa/questions/barrelcodes
There are two screws securing the ramp to the barrel. One screw is quite obvious at the rear of the ramp. The other screw is under the front sight blade. Remove the front sight blade and you will be able to remove the mounting screw.
Check the barrel code on the Remington Society site... http://remingtonsociety.com/rsa/questions/barrelcodes
A darn good site. http://www.urban-armory.com/diagrams/rem514.htm