Trigger Pin Movement

[DJ45]

I have a 9mm Sigma, and put in an Apex Sigma Spring Kit in it. Fired about 100 rounds with it with the kit in it without any issues. Today, I went shooting and after about six rounds, the trigger pin moved from right to left, causing the trigger to become gritty and harder to pull. I put the pin back, and about six rounds it did it again. On the second mag the pin would move out after three rounds, almost to the point of it coming out of the hole. The pistol was used when I had it with the original owners wife stating he had about 25 rounds through it. I have put about 250 rounds through it. Any ideas on the cause or fixes?

 

[star1]

Wonder if the pin got put in backward. There is a groove in the pin that lines up with the spring for the slide lock (release)
Norm

 

[The Nothing]

You should be able to feel/hear it snap into place if installed corrected. My pin wasn't fully seated from factory, and did the same thing right out of the box.