With a chronograph some spacing of the pickups are required in order to have a time/distance relationship. At 1200 fps with a one foot spacing you would read .00083 seconds. I do not know what the minimum time interval for modern chrono's is, but that might well be a limiting factor.
Time of flight over 20 yds for the 1330 fps load was .0548 secs, thus an average speed of 1095 fps (Read that as observed velocity over 20 yds)
Time of flight for the 1135 fops load over 20yds was .0626 secs for an average velocity of 958 fps. Thus a difference of 195 fps at the muzzle amouited to a difference of 137 fps at a point inside 10 yds. It is rather obvious loss came quicker above sonic than at any other point & that drag was not linear according to V˛..
