I shot some TNT'S in my .17HMR and they were somewhat erratic, then shot the V-max bullet in both Remington and Hornady, Bingo! Groups tightened right up. The only thing I think is there are such small sizes and amounts of powder or other small differences they are amplified. Just my opinion. Now I hope I have good luck with the 20gr. Hornadys. They really change the game with their penetration. Turns it into a small, big boy gun if you know what I mean. Buckfever