I pickup a Rossi 92 SS 24" Oct barrel 357/38 last week. I had the same issues and you'll probably find that with the sight set as low as they will go the 357 rounds will shoot 12" high at 75 yards. I bought Steve's DVD, about the only thing I saw on the DVD that I thought might help was a good cleaning with brake cleaner. It didn't help and I really don't see anything on the DVD that will help with our problem. I'm a newbie with this stuff so I might of missed something on the DVD.
Steve did say that these guys are "ammo sensitive" and you may have to taylor the ammo to fit the gun. I had some .357 reloads that I bought from a local indoor range that cycled fine through the gun. What I found was the reloads were 20 thousands of an inch shorter then factory ammo.
FWIW, the .38sp rounds shot 4" groups at 75 yards..not bad for a guy that hasn't fired a rifle in years.
Oh yeah, I have read that shooting the gun may help with our problem. I'm going to put another 150 rounds through it this weekend.