Trigger function

[Jim53]

I am new to Lugers and to this forum so forgive me if this question has been covered somewhere else here. I finally got to take my two new (to me) Lugers to the range yesterday. A 1920 DWM commercial in .30 Luger and a 1916 Erfurt 9mm. Both are original with matching numbers. The DWM shot as expected with a crisp and predictable trigger. When I shot the Erfurt for the first time the trigger pull was so heavy I thought perhaps the firing pin hadn't reset. Keeping in mind I have never before fired a Luger. My questions are how do the triggers work on these pistols? Could one or more springs be worn out causing this heavy trigger pull condition or is this a common thing for Lugers? And lastly, if I change the springs would it decrease the value of the pistols? I don't plan to shoot the 1916 very often but would like to enjoy them. Thanks for any help.

Jim