I have two conflicting stories about the ES100..Had a good friend, now deceased, who used a Pintail for all of his waterfowling. Nothing but praise came from his lips about the gun. He shot it for many seasons and upon his death a grandson continued the tradition with the gun and does so to this day.
I bought a used ES100 just before last season based upon my friend's experience. Gun looked as new and handled very nice but I had nothing but trouble with it. Factory or reload, 2 3/4 or 3in, lead or steel, I never got through a full magazine of shells without a failure to feed and/or fire! I call myself knowledgeable about firearms and did all I could to no avail.
Sold it to a friend who wanted to try to fix it................he is still trying.