No1Mk3 SMLE full restoration - from scratch

[Seaspriter]

While most metal won't rust in 10 minutes, perhaps there is still some salt or other chemical left on the metal.

I've used three different solutions, other than oil:
-1) Rust Converter: This is not rust not remover. It works by chemically reacting with the oxidized iron and producing a black paint-like surface. Rust converters are found in automotive stores -- great for old cars.
-2) Rust Prevention Paint: Such as Rustoleum that has a high oil-base that bonds any remaining rust into the paint.
-3) Bluing: This is a different chemical process that creates a stable version of ferric oxide that actually becomes a protective coat.

Of course, you can also Parkerize the finish, but this may be too complex for a gun in this condition.