Bill, not knowing your load composition or method of loading the Spred-R discs I thought I'd offer this up . . . I learned this method several years ago from posts made by an individual by the name of Mike Campbell. Mr. Campbell has done extensive testing utilizing Spred-R discs and he found that by dropping ~1/8oz. of shot on top of the disc eliminates the potential of donut-holing of the shot pattern. Check out this thread and pay particular attention to the posts with pics by Mr. Campbell:
https://www.doublegunshop.com/forums...=335998&page=1
The very first time I loaded a box of Spred-R's using the 1/8oz. of shot on top of the disc I shot a straight at skeet. The gun I shot was a 12-ga. A.H. Fox Pin Gun choked F/F that I once owned and you subsequently bought from a mutual friend of ours. This 1/8oz. of shot over the disc method made a believer out of me.