I have to agree with RIch.
I have a box of chisels, of all sizes and shapes, ones I thought I couldn't live without.
But I hardly use them.
1/16, 1/8, 1/4, 3/8 wide straight chisels will do a heck of a lot of the work, with the 1/8 and 1/4 being the workhorses.
I like a fishtail gouge for a ton of the work, shaping, backgrounding, scraping, inletting, etc. Get one about 6 to 8 mm wide, and #3 curvature. That's the shallowest you can get, then they are also available as straights. I like the #3 fishtail gouge, as I can cut across the grain without tearing. Also use it to pare thin shaving cuts off the sidewall of the barrel channel as I am inletting the bbl. The fishtail is great for inletting the curved section of the buttplate. And across-the-grain paring cuts for inletting Ramrod pipes.
An X-acto knife is handy, or a bench knife with similar blade shape.