Improve the case means you increase the efficiency of the case without pushing the pressure to dangerous levels. Some case really benefit from improving and some don't . Cases that have the most benefits are the 22-250, 257 Robert , 250 Savage, 280 Rem , 243 Win and some that don't are the 30-06 , 270 Win , 25-06. Gaining 100 to 200 fps sometimes is the difference between a Magnum and the Standard Cal's. If you don't mind the fire forming of the case then the Ack can give you close to magnum performance in a standard cal. I like them, another plus, it almost eliminates trimming cases.
