More of a tung oil fan, then a BLO for walnut.  
On something like birch wood, the BLO works better, since it first going to get stained to unify the stock in color, and your not trying to bring depth to the grain since it will not highlight well with the mulitude of different colors in the wood.

Hence on something like walnut, Tung oil brings out the grain so much better since it slightly darkens the wood, plus gives depth to grain as well.   Plus, with tung oil finish, its a lot easy to touch up if needed, with just having to rub a few more coats in.  With BLO, it will produce a good grain finish, but does not give depth to the grain instead.  Also to point out, the more coats you rub in with BLO on walnut, the more yellow the stock becomes isntead.

As for Tru oil, it BLO base, so although is will produce a hard finish due to the vanish in it, but your back to the same problems as BLO stated above.

Truth is, your not so deep into the finish that you can strip the BLO to start over again.
Do a acetone wash of the stock to pull the BLO out, then let it dry.
From there, you can do a quick fill of the grain and knot voids, first saturation coat with Tung oil, then rub about 3 to 4 coats of Tung oil into the stock  a day apart to finish it off.

BLO on the right walnut stock, left stock is birch; and as you can see with the birch stock, really need to stain the wood to unify it color from the start instead.


Teak oil finish top, while tung oil finish bottom.
Note, although teak oil will bring out the grain a lot better then even tung oil, before going this way, use a wet wipe down of the stock with mineral spirets to get a over all look of the grain of the wood.  Hence if the wood is not really unform in grain and color, the Teak oil finish is going to high light the off-ness/Funkyness instead.  I bring this up, since on a rifle where you have the butt stock, and the a seperate forearm piece of wood, if the two pieces of wood are not almost the same, then your better off with Tung oil, the teak oil instead.

The only thing wrong is the transition between the pistol grip and butt, the line is nearly straight.  Make it either parallel to the forward edge of the pistol grip, or flare just slightly wider toward the bottom of the stock.

I don't think there is much you can do about the blending of the pistol grip into the forearm, from here the blank looks like it is too thin for much choice.
What you can do about that transition is make intentional transitions from curved to flat and control the shape of the transition.  That one is pretty good, the line curves nicely, but it has a little duck tail at the bottom end.

The nose of the butt stock at the pistol grip is too thick.  Look at the stocks here for ideas:  https://www.trackofthewolf.com/List/Item.aspx/487/1  Once you get a trigger guard made up, go after the blend of the forearm all the way to the pistol grip.

I think the stain color difference is due to grain density.  Overall, you did not apply anywhere near enough stain.

You could bend up a trigger guard from a strip of brass or mild steel.