How to fill chips in Marlin 1895 stock

I bought a Marlin 1895 NIB a little while back, and it has the crappiest wood I've ever seen on any firearm. Unfortunately, after searching online and handling about 15 Marlins during one of our last gun shows here I've found my rifle to be the norm of what Marlin is turning out these days since their Remington takeover...

Point being I'm refinishing the stock and forearm so that they are acceptable (hopefully even better than the best one could ever hope for from the factory). I've already stripped the Mar-shield off and am looking for a way to fill all of the gashes/poor milling, and hopefully the 1/2 mm gap between the side of the tang and stock. I've used Elmer's wood filler in the past, but it's not very dense. I looked at minwax wood putty, but it says it never dries and can't be finished over. Is there anything out there that would work, that hopefully could be bought locally? I'm looking to put a poly coat on afterwards.