I havent noticed any leading, but I've only shot a half dozen at a time. I don't know the velocity, but my intention is for low velocity, mainly "enough" to easily reach 30 yards or so for small game shooting, and not too much in that they are pretty quiet to shoot. I've loaded similar rounds for 30-30 and 45-70.
I've had ignition consistancy problems in 30-30 with 3 grs Unique, so I use a very small tuft of Dacron pillow stuffing over the powder. They then worked very well. I read in Greg Mushials site on low vel load developement that they had good results with some powders regarding consistancy with very light loads and no "filler" or dacron fluff, and not so good with others, Red Dot was one of the powders that worked well without any help, so I've been trying some out. I havent really pursued it hard, just loaded a few rounds and went bird hunting after shooting a few shots in the yard. I plan to tinker with the loads a little to see what the most consistant accuracy will be. In an old American Rifleman reloading book I have from the late 50's, they had a piece about extra light loads in various centerfires. They said a small powder change can make a noticeable difference in accuracy. I just haven't taken the time to work with it yet.