Posting this for the DIY folks. I'll be doing a step by step process for you folks that want to finish your own stocks. Hopefully @Forum Boss will make this a STICKY for easy future reference. Please refrain from posting comments as I have a lot of typing to do. For this demonstration I'll be doing a Borden fiberglass BR stock. Stock is raw out of the mold. I start by blocking the surface with 80grit sand paper on a HARD block this will expose the low spots that need filling. These are the dark un sanded areas, you can also see the seam from the mould process. after blocking surface thoroughly you'll need to come back and sand any remaining low spots or mould seams for filler to adhere. when spreading fillers I find it better to get a good amount of filler on and not try to spread it smooth that's what the block and sandpaper is for. I'll use 36grit for my heavy carving/shaping be sure to leave filler a little proud. Next I switch to 80grit and finish blocking the 1st coat of filler. Here I'm moulding the butt with filler, this stock will have a painted butt, no plate. this shot shows 1st coat of filler sanded in 80grit ready for second coat of filler.