After you cut the profile the barrel should be inletted first, then the lock then trigger. After all the above are fitted then shaping the stock can begin. Look around for a book on rifle building too, that would be a great help.

Both of these I built.
The stocks started out looking like this.
My latest project.
Rough profile of forend, this will be a full length stock with the ram rod fully enclosed, a pistol grip will be shaped latter.

Roughed out the barrel channel with a router.

Roughed in ramrod channel with router.

Barrel channel about half done.
And that is as far as I have gone.