That's good shooting Mark - I've only managed 3 in a row continual shooting - twice - and they were 2 Sundays in a row as well, one with the .40 and the other with the .58 Musketoon - course, they shoot big balls.
Possession of ANY split playing cards is good shooting - there are lots of shooters and some normally good shots who have possession of none. Match gitters and a negative approach to shooting the thin black line cause off-shots for everyone, now and then. I've also missed three shots in a row - sometimes one is 'on', sometimes not. The more you shoot, the more 'on' times you'll have.