dragman
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Trevor60 said:I will be the contrarian in this case for argument shake. When you look at group size; one could be twice as big as the other while only gaining 75fps gaining approx 2.5% in speed. But when i run a 6mm bullet with a .272 g7 i see a .2moa difference in favour of the faster bullet at both the 800 and 1000 yard targets. .2moa at 1,000 yards is 2 inches wind drift against a 1" disadvantage in vertical.
This is not an absolute gain of 2 inches as the 2" group would be larger horizontally as well as vertically and would cut into the horizontal advantage.
Using F class as the reference as i do not know silhouette target dimensions the difference when shooting F class would be a clean 10 vs. an outer 9... 2" is 1 5/8 larger then the difference in the ring diameter. But the difference in vertical would only be 1" of a 5 inch circle at 1,000. percentage wise the .2moa group is 40% of the X ring while the .1moa group is only 20%
I have analyzed the same groupings when picking a load for myself with the 308 but have chosen the higher speed as it had a better drift advantage then i was giving up in vertical, my 2 loads were 150fps appart yet the vertical grouping difference was less then 1.5" at 1,000
everything is relative as you say the .1 group is actually .1ish that could be .12 or .16 the closer to .1 the harder it would be to justify taking the faster round.
As a side note i have taken the tighter shooting bullet when shooting a smaller targets. I was testing BIB's 187 at 300 and they shot outstanding against another bullet with higher BC (matrix bullets) but at 300 because the F class target is actually smaller then .5moa i chose the BIB's as what i gained in a reduced vertical outweight the wind drift advantage.
that is some of the math that I wasn't sure of. obviously if there is a huge difference in group I choose the tightest one, but if you have two groups and one is only sightly larger but way faster than in SOME cases it is the more accurate load for down range.