Originally Posted by
ptdunk
Along with the fine level of trigger adjustment I think the spring being in three well finished sections is a strong sign of an intention to experiment with different setups, and in fact if the power was to be changed with different spring section combinations then the trigger weight would have to be changed accordingly to give a safe amount of sear engagement in relation to the strength of the spring. Not something that someone just making a project gun would probably consider...
Maybe having to remove the sideplates to adjust the trigger meant that the user could get a visual impression of sear engagement etc. while adjusting the trigger, which may have been more useful for experimentation than simply adjusting the trigger blindly from the outside? Just an idea.