I’d just concoct a similar load for hiking/camping/hunting and load an ammo can full of it for about what the Buffalo Bore costs. IMHO BB is making this for folks that don’t handload. Get some Starline brass, a couple pounds of Unique, a brick or two of primers and several pounds of wheel weights.
I normally carry factory for SD against two legged predators but the BB 4E is going to be a bit over penetrating for that role in an urban setting. If someone attacks me in the bear woods I don’t care what’s in the gun, and a rural Grand Jury probably won’t either.