Appreciate your input. I have been loading lead field loads since I was a boy, and had settled on my favorite loads years ago, since I tend to use the same shotguns. This lead-free stuff is pretty new to me. For one thing, I can't believe people are getting 1650 fps from tungsten and bismuth. Holy smokes.
One thing it took me a couple of reads of your post ... maybe you meant the opposite, but:
"The large pellets are not needed at the range the smaller ones are lethal while the smaller pellets take up space needed for more large pellets to produce adequate pellet count beyond the lethal range of the smaller pellets."
Everything I've seen with tungsten duplex loads stacks the smaller Tungsten in the bottom of the shot cup, larger steel or even lead up front. The smaller tungsten pellets are the ones that retain lethality at longer ranges, due both to retained energy as well as pattern density. The bigger, less dense pellets are intended to address shorter ranges. So there is nothing beyond the lethal range of the smaller pellets.
As to the 70-yard birds, the jury is still out here, as I have yet to fire even one tungsten load. But I will say I remember in pre-rangefinding days that a plus-400-yard rifle shot was something. Post rangefinders, heck it seems double that distance is a chip shot to a lot of folks. The 70 yard number was more a restatement of what the gel penetration calcs spit out. We'll see how that transfers to the field for me this coming year. I suspect we'll see enhanced ranges. How much? Dunno yet.
The 1.5 gel penetration is just a standardized way to compare. I think for geese they use 2.25 inches. Suffice it to say we could agree on whatever standard you'd like, and then alter the numbers. The idea is to have a constant as a basis of comparison.
Have you gotten to shoot any tungsten? Most guys are using it for turkeys, which mean a lot of the load data is way too heavy. Some of the waterfowl data sure looks interesting though!
