Yes they make a difference. Sometimes a very big difference depending on some factors such as jacket thickness, coatings, or total bearing surface.
Pick the data for the bullet type closest to the bullet you are trying to reload, but heavier. Then reduce by 10% and load up, or start at the starting charge if there is one listed. I've been doing that for a long time now and haven't had a blow up yet.
Machine guns are awesome until you have to carry one.