Try Formby's Refinisher to remove the finish. If you go easy you may not take all the stain out of the wood. Light sanding and then us a spray bottle of water to "raise the grain" and remove the "hair" from the wood with light sanding using 400, 600, and 1000 grit paper. Aldo find some bronze wool in 000 or 0000. Don't use steel wool and be sure to use a good tack cloth to clean the dust from the wood.
I use Linseed oil and rub it on the stock and as they say, "work it". Alternate from oil to sanding with 0000 bronze or 1000 grit sand paper. If you are staining, put on a layer of linseed oil and then stain, then oil, oil, oil with sanding in between coats.
Depending on what you want, it takes time as you can get a good M1 military oil finish or go all the way to a hard Griffith and Howe smooth oil finish. It only takes time.
The raising of the grain was an important step for me to get a better finish on the wood. Google is your friend.
You can also use an iron with a wet rag to get rid of gouges in the wood. I was amazed at what that would do to a beat up stock. Bought a lot go cheap Garand and 03 stocks in the day that really cleaned up with an iron and a wet rag.
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