Tucson:
I'll second the motion on the clip latch/clip latch spring and the clips.
Here's a pic of where to grease the M1:
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You can use just about any good-quality grease, although the "classic" is "Lubriplate." I've personally used that, gun shop generic gun grease, and auto store hi-temp bearing grease. The principal is
oil protects; grease lubricates.
You'll know the rifle is properly greased if the empty casings are ejected at 1:00 - 2:00 o'clock relative to the line of fire.
You might want to check the operating rod spring as well, "just in case."
Hope this helps.