It probably won't effect it much. I used to do alot of Deer hunting in Upstate New York...the only Gun allowed was a shotgun, either with slugs or buckshot. To get ready for the hunt I used to make sure I could hit a paper plate at fifty yards. I didn't plan on taking too many shots further than that. I doubt a little powder residue will cause enough change in slug trajectory to effect the bullet enough to see even a slight difference in this distance shooting. It could if you plan to attempt a shot at a farther distance, but I doubt it. Good-Luck.