In LE, #4 buck is used for situations with excessive penetration concerns.
You want more, not less. 00 or 000 buck. Fed. Tac with FliteControl wad tightens patterns up enormously and penetrates well--lower velocity and all. Same for Hornady TAP which uses same wad, but lead instead of plated shot.
Or opt for standard buck loads with 00 or 000.