The current trigger system which is a modified Miller. My understanding is that Howard Miller felt that he did not receive enough recognition for his efforts. Also, the K guns look to be very complicated,but,after twelve or so years of taking them apart and putting them back together, I find that a complete disassembly,clean,and reassemble takes three hours.I have found that the K trigger is very reliable and the 30 or so K guns that I mantain usually go for 30,000 or more shots with no trouble.