Dirt moving is limited to 100 yards a year without a permit (because we have stupid city people who can't keep their noses out of other people's schitt), unless it's for an exempt activity such as building a road. I'm not sure they'd buy that I needed to regrade 700yds of the East edge of my lot for a "road".
I'm zoned Ag, so I have statutory protection from just about every possible nuisance complaint they could dream up. Proficiency with firearms is a vital component of keeping livestock safe from predation.
But building the facility I want is not exempt in itself.
Grading is a possible option. I have a mix of mostly sandy soils. The firing line is also elevated in relation to the backstop end of the range by a factor of 15-20'. Lowering the range below grade with a dozer would produce the needed spoils for the berms, but would fall under the CUP for earth moving and the county would likely put onerous conditions on such a conditional use. I'd rather keep them out of it entirely, as it's supposed to double as a wildlife clearing when not used as my rifle range (at least until January of 2021 when my SIFA covenant is terminated).
The Hesco gaylords look like an interesting option if their price isn't unfavorable. I wonder if that's something which could be acquired "used" or maybe surplus new?
https://en.wikipedia.org/wiki/Hesco_bastion