mossberg 835 not functioning help

[SCREAMINREELS]

I forgot about this gun but plan to make it a project now I have a Mossberg 835 that's rusty with a barrel I removed. I plan on changing barrel for home defense now.
the problem is the guns basically a single shot will shoot fine but when you rack it the next live shell falls out of the bottom. its missing the "door" not sure of correct name could someone tell me what this part is and if you think tits all that's needed, is it something I can fix myself bought it for almost free a long time ago and forgot about it. will post a pic in a second

[LuBowhunter]

It's missing a $10 piece. Open the action take a picture of the inside so I can confirm for you.

[SCREAMINREELS]

Bottom pics action closed

[SCREAMINREELS]

Action open pic of bottom

[SCREAMINREELS]

its also the Mossberg 835 "ultimag" says 2 3/4-3 1/2 inch shells if that makes a difference

[LuBowhunter]

Yup missing the elevator.

[SCREAMINREELS]

When I looked up pics I believe the silver in my pictures below is elevator?...and yes its filthy I got it out of a barn with the action open....who knows how long it was there before I got it.