The tune-up kit includes the M-K Replacement Spring kit and 2 Hammer/Trigger Pins
The pins are for use in an M-K trigger equipped lower receiver using the large Colt type 0.170 Receiver pins.
Tune-up kit includes:
2 Large Colt type Hammer/Trigger Pins
1 Hammer Spring
1 Adjusted Trigger Spring
1 Unadjusted Trigger Spring
1 Heavy Duty Trigger Spring
1 White Heavy Disconnector Spring
1 Blue Medium Disconnector Spring
1 Red Light Disconnector Spring
The adjusted trigger spring is set from The Wisconsin Trigger shop to give your AR-15 approximately
4.8 pounds of overall pull weight. This is when using the blue medium disconnector spring. This is the configuration your M-K trigger was set to when it was new.
With the unadjusted trigger spring the shooter can adjust the pull to there desired pull weight below 4.5 pounds if they do not have a need to make a minimum match weight.
The green heavy duty trigger spring will add approximately 1.5 pounds to the first stage of the M-K trigger. The extra first stage pull gives the shooter a very solid feel for the trigger even when using shooting gloves.