As Cynthia said, it seems the Colts with the short front sights were originally designed for to be dead on at 75-yards. At least that is what I've read.
I have an 1860 Army and an 1851 Navy (although the Navy is in .44 also). Both shot high as expected. To make matters worse, I like to shoot 30 grains of 3F because it like the gun to "belch", if you know what I mean? :haha:
There is three things I had done to both revolvers: 1)A 3-3 1/2-lb. trigger job, 2) an 11 degree cut on the forcing cone, 3) a taller front sight.
Now both pistols shoot right where you point them. It's amazing what those 3 things do for the Colt revolvers.
Trouble is, no one makes what we might call a somewhat authentic "looking" taller front sight. The two I have, I bought from Kenny Howell (of colt conversion fame). They look natural on the barrel and are a dove tail. Kenny said he designed them for his conversions to be pretty much right on at 25-yards with little or no filing for the .44 and a little filing for the .36. I just wished he had these front sights more readily available. It took me a year of pleading to get the two sights. I wanted to buy six, but gave up after the two. Guess he's just too busy.
But those three things sure made all the difference in the accuracy of the Colts. Rick. :hatsoff: