I'm no loading expert by a long shot.
My buddy that owns an ammo company told me that shot like Bismuth and Tungsten Matrix will generate higher pressures because they don't have the "give" of lead shot ?
The 1 & 5/8oz. lead load I use in my 10 ga. chronos at 1290 fps...
Using the same primer, hull/wad/powder components with a 4 grain reduction in powder with a weighed 1 & 5/8 oz of Bismuth it chronos at 1260 fps.
I can't say how much pressure increase or velosity increase I would have had if I had just left the powder charge alone but according to him it could have been an eye opening amount.
