Theres very few antique handguns that can shoot factory ammo as its loaded now.
So i would plan on buying reloading gear of some kind.
you need to know what presures your loads produce and if the gun your shooting can handle that.
As to the best big bore CF handguns id look at guns that can shoot theses ammos.
44 Russian
450 adams
455
dont forget most guns that are 476 cal can shoot 455 no problem.
45 schofield is a great caliber tho finding a gun that can shoot it can be hard to find.
45 acp is a great round there are antique webleys converted to it and there French 1873s converted to it as well as SAA Colts ect .
Some guys get away with shooting factory ammo in 45 Acp converted antiques but its not recomended it will shoot most guns loose over time.
So again reloading is something to think about if your getting into antique handguns. its so easy a cave man could do it so i dont know why some guys balk at it.
Cost is not even a factor as it saves you money in the long run and lee makes cheep good stuff to get you started.
You can buy cases and componets for the above stuff track the wolf has alot and there Canadians selling alot of stuff others can list there info i dont have it handy.
My favorite guns are webleys 455-- Remington 1875s-- SAA colts in 44 Russian / 44 special ==S&W DA and NM # 3s.
S&W Schofields.
Some guys like 41 long colt i used to but find getting the components can be a pain.
1873 French guns converted to 45 Acp are good starters at under $1500 for a good one there solid frame and strong.
I like SAA Colts and remys because there soilid frames are strong as i like to shoot custom reloads.
Books to start you off.... best book i ever read as i frist got into this was SIX GUNS by Elmer keith.
You can learn alot from him if your wanting to.
Below is a picture of SAA Colt converted to 44 sp that i have its about the best sAA colt i ever had and it shoots to point of aim there strong enough that they can shoot factory winchester cowboy ammo in 44 Sp
Its a very expensive gun took me years to find it has antique pearl grips to.