Tru oil, what's actually in the stuff?

My apologies if this topic has been discussed previously, tried to do a search but nuthin...

so, my question is this. Apart from Linseed oil, does anyone know what else is in the stuff?

I knew a old chap who made gun stocks and did the full hand cut chequering thing and he hated the product.
He was telling me that he had a few stocks come in for some maintenance and when he re cut the chequering his tools would go blunt way to quickly.
his theory was there must be ground glass or silica in the product.

can anyone confirm or deny this theory and, if possible, please tell me what is it that allows for such a high gloss to be obtainable from what is basically a Linseed oil?

Thanks heaps :)

The following is a link to the Material Safety Data Sheet for one brand of Tru Oil Gun Stock Finish ....... https://www.birchwoodcasey.com/getat...Sheet.pdf.aspx

Unfortunately, in the ingredients, they have stated that one of the three ingredients is "MODIFIED OIL (PROPRIETARY)", so afraid that's possibly not much use, unless someone with more experience reading MSDS documents can glean some more information.

Regards,

RoyG