I mentioned earlier that a reason could be because a pellet with a lower BC that will slow down quicker and the revs will be slower down range could be affected by the wind differently so they all end up at the same vertical poi at the same time ...
... but I dismissed that as the chances of the crossover points being at exactly the same range that the testing is been done at ( 55 yards ) is silly.
I'd say the same for the barrel vibration ... that a pellet leaving at a slower speed is launched with a greater loop than a faster pellet that is flying straighter ... the chances on their cross over points being at exactly the range the test is taking place is too silly.
I rather like Rob's comment that we are getting confused with a 40fps difference at the muzzle would make maybe 15mm different impact point 55 yards away. However a 10fps difference at the muzzle would make little difference at 30 yards. At 30 yards the difference may have only been 20fps ( that's why I also said earlier that the test should be done indoors with a chrono at the muzzle and a chrono mid range at say 30 and then another chrono at 55 yards ) to see where the difference opened up.
This may not be right ... but if the difference at the muzzle was say 10fps ... at 30 yards we'd expect virtually the same poi. So if we now started both pellets at 30 yards and the difference is now 20fps then at 45 yards ( so that's 2 pellets now leaving that start point with a 20fps difference and travelling another 15 yards to 45 yards ) we'd expect virtually no difference again in poi over that 15 yards. So at 45 yards the difference is now 27fps ( so that's 2 pellets now leaving at the same start point with a 27fps difference and travelling another 10 yards to 55 yards ) we'd expect virtually same poi over that 10 yards. At 55 yards it's now 40fps difference but we aren't judging what happens next. So maybe all those 'virtually the same' poi's may add up to just a few mm which is what we see on the targets at 55 yards ... but we are judging as if it's 40fps at the muzzle ... but it only reaches that 40fps difference at the 55 yards so the difference we would expect would be happening over the NEXT 55 yards.
Got go get the missus from work.
Last edited by skires; 3rd October 2013 at 02:06 PM.