My stock probe on my impact is smooth. Ordered a new probe from fx and it has some texture on it. Also the back end it longer and they stamp the caliber. The old one doesn't have it. Its weird why they would of put texture on the probe. Wouldn't it seal better with a smooth probe? The texture kinda feels like nail fill but not as deep so I guess doesnt matter much but I perfer it being smooth. I get 15 fps more on my stock probe but that's due to removing to O on the probe.