Generally speaking there is not much difference between makes and models of cartridges they all go bang (most of the time) apart from antimony content, length of brass and quality of powder. What sets expensive stuff aside is that apart from using high antimony, deep brass and good powder the quality control is meant to be better. Expensive stuff such as £240 per K has a cartridge tested every few thousand (apparently) were as cheaper stuff gets one tested every ten thousand or so. This is "supposed" to ensure consistency through the slab and through the batch BUT it would appear that this is sometimes not that reliable.