[BlackKnight]

Originally Posted by AFJuvat

As it happens, I do firearms restoration as a hobby.

I agree, if it is a piece that has collectable value, it should be left as original as possible.

But, to expand on what Charlie was mentioning earlier, there are two different techniques for restoring a firearm.

Restoration: Bringing the firearm back to a new or original state.

For your rifle, this would not be appropriate, but the second option:

Preservation: Stopping or halting active deterioration of the firearm or its components while preserving as much of the original finish as possible.

If you have active rust on the firearm, it needs to be removed and halted.

Try this for a low impact method of removing the rust, stopping any further rust, and still keeping the finish original.

Brush off any loose rust.
Clean/degrease the areas completely. Use denatured alcohol or acetone.

Once it is degreased, do not touch the areas without wearing gloves.

Boil DISTILLED water on your stove.

Either submerge the part in the boiling water (it it is small enough) or hold the part in the steam for 15 - 20 minutes.

If everything was cleaned correctly, the red rust should turn to a dark blue-black, which is magnetite.

Rub off any dust with 0000 steel wool

Coat the area with oil Dirty motor oil works GREAT for this.

Allow it rest for about 24 hours.

Clean off the oil and reassemble.

Congratulations, you just did a repair on your firearm that turned all that red rust into black iron oxide and left everything original.

That. Is. Awesome! Thank you!