In my humble opinion buffering will improve any shotgun load. Some guy (Fadala?) did an article in a gun mg about ML's and buffering with cream of wheat, etc. It seemed to work.
It is a lot of trouble, though.
Course some tried using cream of wheat over the powder and under a prb and also found improvement???
The buffering serves to keep the shot from deforming as the soft lead pellets are shoved up the bore. Anything that can keep significant numbers of pellets round will improve patterns. Ideally buffering, a sleeve (cylinder?) that keeps the pellets from deforming against barrel, a good gas seal and cushion over the powder and something over the shot that doesn't get in the way will tighten patterns in all shotguns.
I found that relatively light loads, thumbsize wads of newspaper wadding over the powder and premeasured shot charges tied up in thin "baggies" corners gave good hunting results. I had a gang mold for 308 rb and used them a lot.
(Don't tell on me about the baggies!)
Cheaters used to pour parafin over their shot columns in ctg guns and get fantastic patterns! Them "baggies", cut off with scissors and loaded tie down over light charges put all 225 #6 pellets in a big thumb sized hole at 40 yds! They cause riots at country turkeyshoots.
PS: Thes folks "in here" done forgot more than I know about ML's but we used to kill lots of deer, in the south, with buckshot when we were allowed to use dogs! The patterns of ML shotguns are not much different, nor the velocities of the shot, from cyl bore ctg guns. Lacking any forcing cone they may be better? OO buck carries to better ranges and retains its velocity better than smaller shot, too. Any deer I ever saw hit with a full load of OO didn't go far! They usually tumbled in a heap! Pattern it first, of course, with different buckshot sizes.
:yakyak: