What risky modification can be made to the Howa HACT trigger?

Cutting back a spring and stretching it into position is considered a risky modification to the Howa HACT trigger because it directly affects the tension and performance of the trigger mechanism. Springs are engineered to specific tolerances and altering them can lead to unintended consequences, such as decreased reliability and an unsafe firing condition. This modification could result in a lighter trigger pull that may not be consistent or safe, potentially causing the firearm to discharge unintentionally or have erratic performance.

In contrast, lubricating the trigger assembly is typically a maintenance task that can enhance smoothness and function without compromising safety or performance. Replacing the sear with a lighter one introduces unknown variables that could also affect safety but is not as immediate or systematic a risk as modifying a spring. Adding a shim for better support may improve stability or alignment, but does not carry the inherent risks associated with altering the spring.