Thanks again for all the suggestions. I'll have another go over the weekend although I'm sure no water based stain is going to penetrate so I'll try oil based. The wood in the areas I'm talking about has gone so hard and dense, it's almost like the wood those women's trinket boxes are made from that you see now and again, I think they are made from Yew, rock hard. This is all very strange! The stock incidentally is a Uberti Buntline shoulder stock, I put the problem in this section as I know you collectors do up your stocks more than the firearm guys.
Remember, it is the strongest character that God gives the most challenges.