I have gotten the best accuracy with 130 grains 777 pellets and have only 2" drop from 100 to 150 yds with 2 - 2.5" groups at 150. A good starting point would be 100 grains of either pellets and you can increase the load as long as it holds good groups with up to 150 gr. although I haven't shot up to 150gr pellets in my optima.