THE FAMOUS 6PPC
Developed by Louis Palmisano and Ferris Pindell the 6PPC is the "King of the Hill" in short-range benchrest competition, the most accurate cartridge ever invented. It completely dominates 100- and 200-yard Group BR Shooting. If you want to win in that game, you pretty much have to shoot a 6PPC, or some derivative of the 6PPC design.
Easily made from Lapua 220 Russian brass, the 6mm PPC, like the 6mm BR Norma, has a small primer and small flash hole. The small flash hole/primer accounts for much of the 6PPC's superior accuracy, though nobody really knows precisely how or why. The "short, fat" shape and nearly straight body contribute to efficient, consistent combustion and good "chamber behavior".
The 6PPC's case capacity, case size to bore ratio, and combustion properties seem to be just about ideal for the short 6mm match bullets. A 6BR can come close, but when the goal is shooting "zero" groups at 100 and 200 yards, the 6PPC is the clear winner.
Currently most 6PPC shooters form their cases from Lapua 220 Russian brass. Both SAKO and Norma make factory-formed 6PPC cases, but these are not commonly used. The Sako 6PPC USA is slightly larger, and will not fit in most current match chambers. The Norma 6PPC brass is somewhat softer than Lapua brass. It works fine for varminting or fun shooting, but it will not hold up to the stout loads used in competition as well as brass formed from Lapua 220 Russian.