Now I am really interested. If the problem happens with OEM triggers as well, it means there is something hanging up inside the rifle, and as stated, since a couple of people who used my trigger had this problem, I want to know the solution. It seems that at a minimum I know it is not related to my trigger, but I still want to fix it.
I agree with fnfalman, it should not be happening, so I hate just putting on a bandaid and letting the problem continue to exist. I'd start witht he following:
Take out your hammer. It should be black. Look at it very carefully under a strong light with a magnifier, especially along the edges. Look for small silver spots where the black has been scraped off or is rubbing. These can indicate it is binding somewhere, so it cannot swing unimpeded. Look at the edges that swing past the hammer spring, as well as where they swing past the steel plate that is used to lock the pins.
Look at the underside edges of the bolt carrier and see if there are rub marks.
Take apart and look at the firing pin to see if it is sliding freely, or if there is an edge that is catching.
If you want to see if something is rubbing, degrease it, then color it with a blue or red sharpie (black works, but is tougher to see against black oxide coatings), then cycle it a few times, the sharpie will be rubbed away.
Look at the inside of the steel plate for rub or scratch marks ....
Put the hammer in without the spring and swing it by hand to see if it is catching.
Somewhere in there is a bur or an edge that is preventing a full swing.
If you want to try the spring, it should work with the trigger you have. No need to replace the trigger if you like the way it feels.
