Did you scratch your head and wonder why there was an extra washer left over after the trigger kit install, or did you install the washer in it's proper location along with the hammer spring?

I'm not trying to be a SA but, I've watched a few videos where these gun experts (use term lightly) didn't know where the washer belonged so they left it out. The short stroke kit will not compress the hammer spring as far as the original trigger assembly does so the washer is required. It might not be required initially, but with use, when the spring settles to a lower pressure, it will be required.