I avoid red (soft) maple like the plague. Frankly, I wonder if much of it really is red maple, and not silver maple. On OCCASION, you can find a piece of wood billed as red maple that is nice and hard, but you certainly cannot count on it.
At best, "soft" maple is dense enough and hard enough to be strong enough for a stock, but will still be kind of splitty, and hairy and hard to get smooth. At worst, it is soft as pine, very splintery, and VERY hairy, and utterly impossible to achieve a smooth surface on. I would almost rather make a stock from tulip poplar...at least it has some color. Green and purple. And no, I 'm not recommending poplar for gunstocks.
All this being said while I work on a soft maple stock blank right now...
If your blank is fuzzy and hairy where he milled for the rod and barrel, it will always be that way, and you will probably never be able to get the surface smooth. I have gotten precarves in the past that were this way, and I just simply had to throw them out. Nothing will make that grain lay down. Filing, chiseling, scraping, sanding, nothing. Chalk it up to experience, prop it up in the corner and start over (my rejects go to my 5 year old nephew to play with! And after seeing me put varnish on stocks and set them out in the sun to dry, he had some orange acrylic paint and painted one of his stocks and set it out to dry just like I do!). Get yourself a piece of sugar maple, or even a piece of GOOD quality walnut or cherry (which basically must be picked out in person, given the wide range of quality in these two woods). You'll be happier for it.