I went to shoot my RIA .45 at bullseye practice last week and my POI was very low. I mean like 6-8" low. I had previously shot at my property and had been shooting to POA. After the frustration at Bullseye practice, I had a chance to go shooting yesterday. I cleaned the gun and I was back to POA. I got to thinking about why this would happen. I hadn't cleaned the gun between the range session (100 rounds) and Bullseye. Also I took some American Eagle to Bullseye but shot Federal Champion at my range yesterday. So was it the dirty gun changing the POI significantly? I had shot a box of American Eagle through it previously with good results. I can't hardly believe that my POI would change that significantly.