[JMCCOYB]

Go to: http://www.remington.com/support/parts/obsolete.htm

That in on Remington's web site. They list about 15 dealers who stock various parts for obsolete Remington guns--which yours is one.

Scrol thru the list and find the ones that say they have parts for the #878. I counted about 4-5 of the dealers who have your gun listed.

Good luck.

 

[JMCCOYB]

Or, you can take it to a local gunsmith who will probably charge you all of $20 to do it. Worth a call anyway.

Good luck.