Help, Maintaining Old Eddystone 1917 Rifle?

IIRC those stocks were coated with Linseed Oil. Some say straight LO but the most common you find today is Boiled LO, (BLO). It has a drier added so it doesn,t stay oily. I've used that on Milsurps I own and several other sporting rifles. You basicly get some on your hand and rub a coat on the stock, wait 5 minutes and wipe it all off with a old cotton rag.(Take that rag outside after and burn it or soak it in water. BLO can spontaniously combust and cause fires) Do this daily for a week and see how it looks. Most of the oil will soak in but you can build it up slightly if you do more coats. Now you say it's spoterised. It could have a different finish on it now. Pics would help. Good luck

Looks to me like that is the original military stock, but "sporterized." So Scooter22's advice is probably good unless someone added a different finish at some point. Try the boiled linseed oil. The stock looks to be in decent shape now. A coat or two of BLO will preserve it.