SIG ammo -huh?

I thought I would give sig Match ammo a try. Pictured is what I have - take a look at the crimp. 3 boxes, all with this crimp. What gives? I am open to new and improved things - but - what?

Same crimp on some nickleplated 22 tcm I picked up, something about preventing blowout while maintaining even case pressure/ more even velocity/power.