I completely agree with the barrel length comments and would also ask what Chronograph are you using ?? Are you able to compare your velocity reading with a friend's chronograph ????Also what powder scale are you using ! I always weigh the pan twice . Once when the powder dumps it and the RCBS 1500 beeps , the I gently remove the pan, shake it to level the powder , then re weigh it ! Extra step but it makes me comfortable! So in my mind 40 fps or more , is the barrel length, so now your looking for 60 fps (possibly). If your Chronograph is off by 1 percent that's another 30 fps. ( possibly )So now your looking to find where 30 FPS came from ! IMHO !!!!