Renaissance wax was developed by the British Museum conservation department who were looking for a medium to give long term protection, but that would not chemically react with anything it was applied to and could be removed completely using a solvent.
The problem with any protective medium is the potential damage it could cause in the long term. Natural waxes such as animal or vegetable waxes or greases do not have consistent chemical properties. They may contain contaminants that could react with the artifact in the long term and cause damage. The protective medium itself should not change characteristics such as colour or physical state over the long term.
We do know that some waxes, oils and varnishes dry out and oxidise over time, usually becoming darker and shrinking. This is a common issue in picture conservation where the image can degrade over extended periods because of varnish deterioration. In some cases, the darkening of finishes is acceptable, even desirable. Gun stocks being a good example. We must however be careful to differentiate between desirable "patina" and damaging deterioration.
For protecting iron/steel surfaces it was discovered that dust is a particularly insidious corrosion source by acting a wicking layer drawing moisture from the atmosphere and promoting ideal conditions for rust to form. Oil does not provide a sufficiently permanent protective layer to keep dust away from a metal surface and indeed may encourage dust to collect which then absorbs it. Varnish and paint layers will provide protection, however only if there are no cracks or breaks. A stable wax that is soft enough to fill irregularities and to "self heal" but is hard enough to maintain a barrier below dust and moisture has the best prospect for long term protection.
Renaissance wax is formulated from high specification mineral and polymer microcrystalline waxes primarily designed to be chemically neutral with a solvent base. It is soft enough to apply easily but then dries to a neutral covering layer with no added colour or lasting aroma.
I use a generous coating of Ren Wax to line barrel channels and the inner surfaces of metal fittings. I also use it on the wood and metal of any guns that are in storage or display.