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?