I would like to say a word of thanks to all who contributed to the forums on the Remington 550-1. I inherited a 550-1 from my father, and the entire receiver assembly was so full of gunk, I decided to tear it down completely so I could clean and lube every part. (Even after I read about the hazards of removing the sear spring case.) Because of the information provided by you guys, I completed the project and the gun is now clean and lubed, and works perfectly. I owe all of you (who have gone before me) a debt of gratitude! But, this is what I did:
1.removed the receiver assembly from the stock
2.removed the receiver plug and main spring assembly
3.removed the bolt, firing pin, and handle assembly
4.removed the recoiling chamber
5.removed the sear assembly
6.removed the trigger and safety assembly
7.removed the receiver insert
8.removed the the recoiling chamber

9.cleaned and lubed all (including the bore.) (I saw no point in removing the barrel.) I
cleaned the small parts using carb cleaner and lubed them with synthetic oil.

10.replaced the recoiling chamber.
11.replaced the receiver insert
12.reassembled the sear assembly
13.TO REASSEMBLE THE SEAR ASSEMBLY I:
a.Held the sear and carrier in place with a punch and then drove the pin in.
b.Replaced the carrier tension spring
c.Used a screwdriver (as a pry bar) to hold the sear down to the bottom of the
receiver (this position of the sear will allow the sear cup to be threaded without
cross-threading.)
d.Installed the sear spring, then screwed in the sear cup (by hand, while holding
down the sear with the pry bar.)
14.reassembled the safety
15.reassembled the trigger assembly
16.reassembled the bolt, firing pin, and handle assembly
17.reassembled the main spring assembly and receiver plug
18.rubbed a little “Old English” on the stock.
19.wiped the receiver and barrel down with a thin coat of synthetic oil.
20.reattached the receiver assembly to the stock with the takedown screw.
21.Loaded a couple of snap caps to check the action
22.Loaded a few rounds and….fun was had by all!
Thanks again to all for the info. I hope this post will help someone else with that wonderful old Remington 550-1!