I have a 4 5/8 New Vaquero in 45 Colt. It shot low with everything I tried. Ended up fileing down front sight some. With yours being a 38/357, you might try different ammo to see if you can find a load it likes. Most 357 fixed sight guns seem to be sighted for 158 gr bullets. Lighter/faster bullets often hit lower and heavier ones hit high. A bench rest or a friend who is a good shooter might help determine how much of problem is the gun. If all else fails, call Ruger. Good luck!