SFD's of 75fps doesn't sound like much (as a number), but that represents spreads of velocities up to the 200fps range, shot to shot. Of course, this is totally unaceptable.
: Ripp has a solution, but as all solutions, just be used correctly as he is doing.
: Old loading manuals and articles by 'gun writers' can be misleading to downright dangerous in not used EXACTLY as shown. A certain picture from a manual or article comes to mind of one such occurance, in that it shows a sectioned .45/70 case, with a very small charge of dfast burning powder in the bottom of the case, held there with a tiny tuft of dacron. It is a long way from the bullet. Now, such a light, small tuft of dacron will never ring the barrel, but if you double the amount of dacron, still a long way from the bullet, or change the material to a heavier density filler, and have it off the bullet's base, problems can become real.