Here's a short review on how to install a TriggerTech trigger into your WK180-C.
Those familiar with the WK, know that it has a funky internal bolt catch that prevents the installation of an upgraded, cartridge-style trigger group, such as TriggerTech trigger systems. This is due to the extra material on the bolt catch hitting the trigger cartridge directly below the bolt catch pin on the thick webbing that goes around the pin itself.
If you wanted to install a TriggerTech with the OEM plain Jane internal bolt release, you'd have to go through the trouble of filing the webbing area down a bit until it fits above the trigger cartridge and can freely rotate. Furthermore, installing a TriggerTech with the OEM trigger and hammer pins will result in pins walking out of position over time unless you glue them in place (not an ideal solution).
In both cases, the bolt catch will contact the front corner of a TriggerTech trigger housing near the hammer spring. This will result in a slight, insignificant difference in the position of the bolt catch suspended above the magazine well. The magazine follower will still contact the bolt catch and push it to position on an empty magazine, locking the bolt as you'd expect. This area could be filed a bit for clearance, but I wouldn't if the bolt moves freely with no magazine installed.
Looking for a way you can install a TriggerTech trigger without any smithing involved?
For easy, no cutting/filing installation of a TriggerTech trigger, use the modern external bolt catch release and our anti-walk pins.
The modern external bolt catch release has been thinned out dramatically (about 2.5mm) and has much less meat around the pinhole. This is about the perfect amount of "space" you'll need to install a TriggerTech trigger into your WK with no extra gunsmithing. In this installation process, you will also need to use the anti-walk pins (to replace the OEM trigger and Hammer pins) as well. These pins are designed to be held in place by the "J" spring, in the OEM hammer, and trigger spring on the trigger pin.
That's all you need to do.
Welcome to the world of a match trigger in your 180 pattern firearm!
Note: This information and the parts mentioned above are applicable to the WS-MCR platform as well.