How to adjust the sight on a slug barrel for an remington 870 pump

SOURCE: My 870 Remington 12 ga. pump's barrel now moves

HELLO; Check and see if you have the barrel set into the receiver fully, and look at the receiver and see if it isn't split or the mag. hasn't become loose, I have two of these guns and Ive never had any problem like your discribing, but not to say it cant happen. PS make sure you retract the bolt before you insert the barrel in the receiver. GOOD LUCK....GREASY.

SOURCE: broken extractor housing on Remington 870

http://www.brownells.com/.aspx/pid=653/Product/REMINGTON_870_RIVET_STAKING_TOOL_SET

SOURCE: got a remington bicenntenial 870

The Bicentennial 870 was built in a Trap grade, Skeetgrade and a Trade model. They sould for around $225.00 and were made to commemorated the US Bicentenial iin 1976. Current value on this model in a target grade is around $500.00 and around $400.00 for the Trade model.

SOURCE: looking for manual on remington

http://www.remington.com/pages/news-and-resources/downloads/owners-manuals.aspx