Howdy
Well, you asked for opinions, and in my humble opinion the 'best handling' grip of a Black Powder revolver is the 1851 Navy. That is why when the Single Action Army cartridge revolver came out in 1873 it had the same grip as the 1851 Navy, not the 1860 Army.
The 1860 Army grip is about 1/4" longer than the 1851 Navy grip. Lots of folks like that because they can cram their entire hand onto the slightly longer grip.
I discovered a long time ago that if I try to cram my entire hand onto the grip of a SAA, the knuckle of my middle finger will be in contact with the rear of the trigger guard. If I then fire it with a 45 Colt cartridge loaded with Black Powder, the recoil will slam the back of the trigger guard into the knuckle of my middle finger and it will hurt. That is why I NEVER try to cram my entire hand onto the grip of a SAA. I discovered that by curling my pinky under the grip, my entire hand shifts down a bit on the grip and a space of about 1/4" opens up between the rear of the trigger guard and my knuckle. That 1/4" protects the knuckle from ever getting whacked by the trigger guard. Even with the heavy recoil of a 250 grain bullet fired from a 45 Colt cartridge loaded with Black Powder, it is easy for me to control the recoil. I do not hold the revolver with a death grip, I allow it to rotate slightly in my hand from recoil. This also allows me to cock the hammer more easily because the hammer spur is now closer to my thumb. Then I regrip for the next shot.
This photo illustrates how I grip a Colt Single Action Army. Notice the pinky curled under the grip, and the space between the rear of the trigger guard and the knuckle of my middle finger. Even with a heavy recoiling Black Powder 45 Colt load, I find it easy to control the revolver when it is held this way.
To me, the distance between the grip and the trigger guard is the most important feature of a revolver grip.
This is my old Uberti 44 caliber, brass framed 1851 'Navy'. Yes, I know the 1851 was never made as a 44, but I did not know that when I bought it in 1968. Compare the shape of the grip to the 2nd Generation Colt in the next photo. They are pretty much the same, with the same amount of distance between the grip and the trigger guard.
2nd Gen Colt.
This is an Uberti Cattleman, replica of the Colt SAA. Again, the grip shape is the same as the Colt or the 1851 Navy.
This is my old EuroArms 1858 Remington that I bought way back around 1975. There is less space between the trigger guard and the grip on the 1858 Remington than with a Colt. Not really a concern when firing them as a Cap & Ball revolver, a 44 caliber ball only weighs around 150 grains or so, and the amount of powder than can be loaded into the chambers does not create enough recoil to hurt my knuckle. However when fired with this 45 Colt conversion cylinder, the recoil again becomes punishing because there is so much less space between the trigger guard and the grip. For that reason, I usually shoot this revolver with the shorter 45 Schofield cartridges which do not have the same powder capacity as 45 Colt.
Interestingly enough, when Remington brought out their cartridge revolver in 1875, they lengthened the distance between the trigger guard and the grip. This is an actual original antique 1875 Remington, not a replica. It is pictured with my 1858 EuroArms 1858 replica. Notice the huge amount of space between the trigger guard and the grip. The 1875 revolver is chambered for 44-40, and with my Black Powder loads it is a pleasure to shoot because of all the space between the trigger guard and the grip. With my pinky curled under the grip of course.
This photo compares the 1875 Remington and the 2nd Gen Colt. Again, notice how much more space there is with the Remington grip.
The 1890 Remington had the same grip shape as the 1875 model, the only difference being the shape of the web under the barrel.
This photo shows the difference between a standard Colt Single Action Army and the Bisley model. This is an actual Colt Bisley, the grip shape is very different than the grip of the Ruger version of the Bisley grip.
The Ruger version of the Bisley grip. I bought one a long time ago. Everybody had convinced me I needed this grip to be able to hang onto the revolver when fired with the stout recoil of 45 Colt Black Powder cartridges. I took it to exactly one CAS match. I was not impressed. I sold it and used the money towards my first Colt. Perhaps if I was shooting 45 Casull, or some other mega cartridge I would need this grip shape, but not for 45 Colt.
As has already been stated, there is some similarity between the shape of the Ruger version of the Bisley grip, and Elmer Keith's famous No. 5 Colt.
So that's it in my humble opinion. The 'best' single action revolver grip, either Cap & Ball or cartridge is the one that allows me to curl my pinky under the grip to open up 1/4" of space between the trigger guard and my knuckle. The 1851 Navy, and its decedent the Colt Single Action Army grip do that for me.
