It's already been said, but I too use a block plane, spokeshave, #49 rasp, bastard halfround file, then finally round/kidney shape scrapers. I have two kidney scrapers - one is thicker and the other thin, the thick one I usually keep at 90 degrees and takes off a lot of material and the thin one gets a small bur for final smoothing and fine tuning.
Remember that the shape of the nose of the comb can vary widely depending upon what style rifle you're building. Some of them are quite bulbous and round, while others are very sharp.
-Eric