Not really that new:

October 1904 - this advert tells that: gas is introduced into the shot charge to promote the spreading effect. "Less recoil and practically the same velocity".
http://i1044.photobucket.com/albums/...pso4oq6nac.jpg


December 1904 - no mention how the Big Red W did it in 1904 "without the sacrifice of velocity, penetration or uniformity". I remember seeing a cross-section of a spreader shell in one of my old American Field papers, showing layers of thin card wads in the shot charge. Kind of like a layer cake. But I don't recall if that was Winchester's design. I'll post that illustration when I come across it again.
http://i1044.photobucket.com/albums/...pstivofd1a.jpg

Great information
 

Dave- this is a great thread. thanks for starting it.

Thirty years ago I wrote Tom Roster a letter asking him how I could develop a load that would in effect open up the pattern in a tightly choked Parker 20ga. He suggested cutting the petals off a plastic wad and loading as usual. The theory being the shot would scrub the barrel, slightly deform, and open up the pattern. It worked and I've been doing it ever since.

I am a bit amused by those who do this "spreader" thing for casual skeet. Is there a difference in the annual income from skeet shooting with and without spreader loads? I am interested because it is time to turn my paper over to my tax man for 2014.

Looks like UMC might have gotten some bad vibes on bleeding off powder gases to cause spreading of the shot charge, thereby reducing velocity. This advert appeared on the front page of the next few issues. Humm, let me think about that ..... the new short range shells wiill strike with adequate killing force (at 25 yards) but with almost the same penetration as regular shells would do @ 40 yards.

http://i1044.photobucket.com/albums/...pszso8bjvf.jpg