If your loader is a 600jr you can load 3inch shells, the manual tells you how to adjust the press. Get yourself a Reloading Specialties handbook. My favorite load is #109. I use Federal 3 inch fiber based hulls.When using steel speed is the most important factor. My load calls for 1 oz of shot, which may sound light for ducks but remember 1 oz of steel has the same pellet count as 1 3/8 oz of lead. Always use an overshot card to get good crimps.