Hi,

I will give you a couple of things to check. First is your ammunition. If there is an "M", "N", or "U" it is a 3" magnum and you must use magnum shells to cycle the gun. There is only 1 gas port in the barrel and the heavy load is needed. Some also need a 3 1/4 dram equivalent and 1 1/8 oz of shot. The field barrels have 2 gas ports and are made for the lighter 2 3/4" shells.

The barrel seal will wear and needs to be replaced occasionally. To check it, coat it with gun grease and try shooting a couple of rounds. Also make sure the gas port in the barrel ring is not clogged up. You may also have a carbon build up on the piston and its seal. If the piston and seal are in the wrong way it will also cause cycling problems. Page 15 in the manual shows the proper way to install the piston.

http://www.remington.com/~/media/Files/Owners-Manuals/Models1100and1187.ashx

The action spring will also cause problems. It can get gummed up and prevents the gun from cycling. You will need to remove the buttstock to access it. There is a screwed in plug and a cross pin in the action tube. Remove them, control the spring, it can fly across the room and or hurt you. Clean the tube out, clean the spring and plunger, grease them lightly and reassemble it.

I hope this helps you,

Tom