[Matt VDW]

What is the function of each of the three fingers of a 1911's sear spring?

The left finger presses the sear into the hammer's cocking notch, and the middle finger presses up the disconnector, right? But then what does the right finger do?

I've been trying to build a 1911 that won't stay cocked and I think the problem lies with the sear spring.

 

[Shane1911]

Grip safety return.

 

[John Lawson]

The right spring tensions the grip safety.
Before you fiddle with the sear spring fingers, check the hammer and sear out on a gage block. Any tendency of the sear to slip out of the hammer notch due to a rounded configuration will show it self on the gage block. If engagement is secure when you apply pressure to the hammer means that you need to increase tension on the left and middle fingers of the sear spring.
Most cases of the hammer following are due to trigger bounce and/or a trigger with too great a mass. Sometimes, increasing tension on the left and center arms of the spring corrects the condition. The safest bet is to go to a trigger with less mass.

 

[Matt VDW]

Thanks, guys. I should have realized that the right finger presses against the grip safety -- duh!

Trigger mass isn't a problem; I'm using a lightweight Videcki. I think the sear spring was too long, because I just tried a shorter one and that fixed the problem.