For me, LB in 12s nearly matched Hevi factory loads. If the same holds true for the 20s, I can't see them giving density past 40. I could be wrong. All 20ga lead loads prior to the LB sucked at 40. If these will make 40, I can see them having enough energy there. If they make density past 40, it could be iffy unless it's 5s or 4s(which further inhibit density in the 20).