Miguel, they are a bit difficult to load but not impossible and they are fun enough to make it worth the extra effort. I tried them in a Uberti Walker as well as the ASM Walker in the picture. The Uberti has a slightly smaller loading cut out and I had to angle the bullets to get them under the lever. The ASM has a tiny bit more clearance so the bullets could sit straight up and go under the lever but just barely.
Getting the bullets under the lever is only half the battle. The hard part is keeping them straight as you ram them down. Bullets that tilt as you're loading them can sometimes be pulled out. These bullets can be quite deformed. I can see how a soldier might easily think it was a good idea to take the deformed bullets and simply load them back in upside down. I can also see how a soldier might get frustrated and decide to load all his bullets upside down. Of course we know now that experts believe loading these Pickett bullets upside down could cause the cylinders to explode. I can almost gurantee you that if I was a soldier in those days unless somebody had told me not to do it, I would have done it.
I will be posting a target and you should be able to see that some bullets did tumble and keyhole.
Shotgun Dave, thank you! I only took this pic a few days ago otherwise I would have.