If you are going to use Tru Oil gunstock finish, that needs to be put on RAW WOOD. There can be nothing else on the handle to inhibit the oil penetration.
If you are using any type of buffing compound, this will fill the wood's grain and will not let the Tru Oil penetrate into the wood.
If you have gone as high as you are going to go with sanding, then lightly dampen the handle - just a LITTLE! Just damp - NOT wet.
This will raise some of the wood's grain that you actually pressed DOWN into the surface as you sanded.
Let it dry.
Rub it off with some 0000 steel wool.
Do it again.
Do this three or four times until no more wood fibers RAISE when you slightly dampen it.
Run in some of the Tru Oil, just putting a light coat on the wood with your wet fingr tip.
Hang it up and let dry for the better part of the day.
Lightly rub this out with 0000 steel wool.
Repeat.
Repeat.
Repeat until you are pleased with the depth of the finish.
Top coat with Tru Oil gunstock wax.
Forget the buffing.