I recommend against using snap caps for shot gun practice because they're too heavy. I say that because the added weight can let you get away with being lazy and or bad habits when shucking that you won't be able to get away with using empty hulls. For loading weight means nothing. Adrenaline during the stage means you wouldn't be able to tell if the shell weighs 10 grams or 10 pounds. But when it comes to shucking spent hulls, weight means a lot. Use empty hulls for more realism and thus better practice.