Ok so I may get some flack for this but hope not too much. I have a Savage model 340 chambered in 225 Winchester that I am looking to make my primary groundhog gun. It does not seem to have any collector value even though it is not that common. The stock that was on is a walnut stock with some checkering. Now a disclaimer, somebody refinished the stock at some point, sanding at least some into the checkering. As a result, the checkering looks "muddy" and not very sharp at all. Since I am the type of guy that tends to scratch wood stocks, I was wanting to do the "marbelizing" job on the stock. My question concerns the existing checkering. I am figuring i need to cover it somehow, and am not sure how to go about it since the checkering that is left is not that deep at places. I was thinking wood filler ( i worked with furniture so I feel comfortable with that). But is there another method that would be easier/ hold up better? What about a "filler primer" something else? I am afraid if I let it the way it is now, several coats of paint will make the checkering look even more "splotchy".

I personally would leave it as is. I refinished a stock in that same condition and I liked the way the shallow checkering added som grip.
If I was to fill over the checkered ares I would prime first, then use glazing putty for the filler.

Get a tool, recut checkering. It’s not an Al Biesen stock that you have. I recut one I was refinishing a few years ago. It looked fine, and I’m not good with things like that. It will look like crap if you try to cover it up.

Used checkering tools are cheap on eBay, that where I got mine. 20 bucks

sand it ,fill anything that's rough,paint it . I could fix it in 2 hour max.

I would re-checker it, but I would buy new tools from Brownells. For an existing pattern, you could redo it with a handle and a single point cutter for under $20. The cutters are small files that get dull with use. Sharp cutters cut sharp diamonds.

I have re-cut checkering and it's not hard at all

As said above....the single point DemBart tool is what you need.

Pretty sure it's pressed checkering on that Savage 340. Meaning it wasn't sharp to begin with. I've seen a boatload of those rifles and never seen one with cut checkering. The stock should be walnut. Only a retard would paint a walnut stock. The same kind of retard that paints a hardwood floor or solid oak dresser. Strip it, sand it, whisker it and refinish with tru-oil, spar varnish or the polyurethane of your choice.

If the checkering was pressed in you may be able to get most of it out by putting a wet washcloth over the checkering and go over it with a hot Iron. This will "Steam" the checkering out and you'll be able to sand it smooth with little effort.