I have a smith 67 that's always shot well, but always has a little leading problem. I think it has some thread choke. Easy target loads leave a little lead at the very beginning of the rifling, and sometimes 1/2 inch down. Accuracy does not seem to be affected, but solving it is a pleasing puzzle in a way.
I've pretty much shot only some shape of wadcutter in it. I had an Ideal lyman 358063 that was a basket case, I tried grinding out the bevel at the sprue end but these new "bases" never were satisfactory. I believe the uneven bases allowed a lot of gas cutting. I now have an rcbs that casts much better, weigh 153gr at .358 (throat size) and are lubed with BAC.
I've almost exclusively used 700x about 3.2 grains as I seat the bullet proud of the case into the throats about an 1/8th inch. Unique was tried at about 4 grains, and no leading was seen I think due to higher pressures, but these loads seemed too hot. Today, I finally decided to try 3.0 gr bullseye. Just had a hint of leading at the start of rifling and accurate. Gun was not as dirty as expected, cleaner than with 700x, so I think the pressures were higher with the bullseye.
Anyway, more playing ahead on these nice spring evenings with an age old problem with boring loads.