The caplocks of the 1850's were the ultimate in fit for game hunting. They raise to the shoudler and the sights lock onto the target just as the butt comes into the shoulder.
With 'some' practise, I found hitting an 8" gong every time at 50 yards offhand was a simple matter of looking at the centre of the plate, bringing the gun to my shoudler and pulling the trigger as soon as the stock was into the pocket - without looking at the sights at all. Simply, look, then gun to the shoudlerboom.
Steve Zihnn of this forum (& Nitro Express forum) makes supurb English Sporting rifles of that period in line with the Purdeys.
Taylor has now made 4 or 5 now, all shooting and fitting as the should, the smallest of .40 cal. with extra .54 cal. barrel, along with another .54, my own and buddy Keith's 11bore.
Here's a picture of 3, spanning the flint period to very early fling/percussion. The top gun is a 6 bore.
Here's my 14 bore
A 20 bore smoothbore which would have made an equally fine 20 bore deer rifle.
Here's a J. Manton 15 bore, side by side 'pelter' of mid 1800's era.