Fantail - if the gun is cleaned, oiled, and has a newO ring -and used to run with regular ammunition . . . As far as the pitted chamber goes, if you know someone who has an 1100 non-magnum barrel in good shape - you might see if you could borrow it to try on yours. If it runs with their barrel, then you have isolated the problem. If it still doesn't, however, then you need the services of gunsmith familiar with all the little quirks of the Remington 1100. Good luck. Roscoe