Thank you for your purchase of a Mainspring Industries CZ/BRNO trigger kit. First and foremost is firearms safety, always make sure your firearm is unloaded before beginning the installation of any parts from this kit. Always assume your firearm is loaded at all times and keep the muzzle pointed in a safe direction and your finger off the trigger. We recommend that any modifications to your firearm be done and tested by a competent gunsmith.
You will notice you have four shimming tubes, one ten thousand of an inch (blue) one twelve thousand of an inch (green) one fourteen thousand of an inch (black) and one sixteen thousand of an inch (red) as well as four springs varying from one half pound to three pounds as well as a 3/32 roll pin to replace the old trigger pin that pulls on the sear.
1) Note assembly of your trigger guard and magazine, leave bolt in receiver, remove action screws and remove barreled action from the stock.
2) You may have to grind the ends of the pins holding the trigger to the receiver (A) before removing them with an eighth inch drift punch. Remove front trigger pin first followed by the rear trigger pin. Now the trigger should be free of the receiver.
3) Place shim tube between sear and receiver,(B) the size of shim required will require remounting the trigger and checking sear engagement, the front trigger pin will now go through the tube and this will keep it in place, replace the old trigger pin with the new roll pin supplied.(C) Usually starting with the largest shim and working down until the sear engages then going down one more size for safety, there should be around 14 thousands of an inch of sear engagement for a properly operating trigger.
4) Choose the spring that best suits your shooting needs, we don’t recommend you go below two pounds of trigger pull for safety reasons.(D)
5) Always confirm your trigger pull with a trigger pull scale and or the bump test (a good blow to the butt stock of an assembled rifle with a rubber mallet) to ensure it is within safe operating specifications.
Design of this trigger kit will provide lighter trigger operation, and will require firearm to be handled with care. ALWAYS close bolt slowly and keeping the muzzle pointed in a safe direction when loading or unloading your firearm and NEVER rely on your safety.