I have an older Remington 1100 that will not completely chamber a round or close over an empty chamber- the bolt stops around 1/8"-1/4" short. Any ideas on what might be causing this and how it can be fixed?
You need to remove the bolt and buttplate; then remove the recoil spring. Spring might be OK but the housing tube could be crudded up. EZ to clean with a proper dia bore brush. Might as well put in a new spring; only a few $ and the teardown is the hard part. Be sure to clean housing ID thoroughly regardless !!
Check the strut on rear of bolt also; could be binding or galling on the spring follower.
Hint: to remove the buttstock side spring retainer nut make a XXL slotted screwdriver out of a spade bit with a hex shaft that you can chuck in a socket wrench. Some of those retainers are on TIGHT. There is a new style hex OD retainer nut but if you just grease the threads and don't overtighten on reassembly you can reuse the slotted style. Its always under spring tension preload and unlikely to loosen up if snugged down firmly.
Remove the bolt and examine the top rear, mostly left side, for gall marks. A gall mark is where metal rubs against metal. If marks are on the bolt then you should find rub marks where it rubs on the receiver too.
Grind that section of the bolt smooth and your good to go.