I have carved out both shotgun and rifle stocks. Even if you are familiar with working with wood it can be daunting.
First you'll have to check the moisture content of the wood to see if you can even have it carved. You may have to wait months to years before it is ready. .
Then if it is something you really want to do I suggest you find someone who has a stock duplicator and have them do that for you. They will take care of all the more difficult machining and shaping leaving you with the final fit and finish. Sounds like you're cheating but you're not. Final fit and finish is quite intense to get it just right. A lot of fitting scraping the high spots and fitting again. When I learned gunsmithing I was told that sandpaper is not a stock makers tool. Wood scrapers are your tools of choice. You'll also needs some Prussian blue which will help with the fitting of wood to metal. You'll also have to finish shape the stock and fit either a buttplate or pad. You will have checkering to do and final finish after that. If you've never checkered I would definitely suggest you get it professionally done. It is easily screwed up.
Lots of steps and time involved to get it right but when you're finished you'll have a really nice stock that you can take pride in.
I don't want to sound discouraging but be frank and honest with yourself before you start. It will help you with making a good choice or wasting a good piece of wood and being disappointed.
PS: Working part time on final fit and finish takes me months to complete. So patience is a true key...