I am wanting to build a varmint pistol but don't know where to start.I am looking for a good caliber for a for Coyotes, Rock Chucks,and Sage Rats.It will be used to mabey 200yds.It will be on a REM short action.I have narrowed it down to a few but still to many.204ruger,221rem fireball,223rem,22ppc,6mmppc, 6mmbr.Do you guys have any sudgestions on calibers.Also who makes a good walnut or syn. pistol stock.