[GSlob]

"tradeoffs must be made between range, accuracy, weight and barrel life."
That's where the barrel metallurgy comes in play. It's no longer Long Bertha with its barrel life about 60 shots till re-boring.

[ArtyFO]

I believe the South Africans came up with a cooler burning propellant that lengthens barrel life, ie can take more firings until rebore.