Is there a calculator out there that will give me an actual (predicted) muzzle velocity correction based on how far the Chrono was from the muzzle? I was doing some load development today with my new 204 ruger build but the hay was so high I had to sit the Chrono twice as far away as I usually do to get it on the right height. For what its worth accuracy seemed to get better as charge weights increased. At 28grs of 4895 under a 40gr V-Max I got very light primer flattening and 3878fps 30 feet from the muzzle. Barrel is a 10 twist Shilen. ES from charge weights 27.8 to 28 was only 15fps.