So that would be the same as a 845fps +/- 15fps.
You might have picked those numbers out of you head, but are really pretty close to what you'll see over a 25 shot string. Will be a run in the middle of less +/- 5 fps.
How much difference does that make in point of impact at longer ranges (like 40 or 50 yards)? Depends on how accurate the gun/shooter is....may not notice a 1/3 or 1/2" difference in impact on anything but paper...may turn a skull shot on a squirrel into a jaw wound.
For general shooting, will take a +/- 2% (with a 845fps average, can call that +/- 15fps). When seriously hunting, will try to stay in the best of the sweet spot and look for less.
Shot these 5-shot groups at short range (20 yards), not using the best shooting pellets but at least good enough to show the up and down nature of the point of impact as vel. rises and falls. Vel. readings were at 6 yards, so can figure muzzle velocity was closer to 15fps higher than listed.
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It won't get better with more range, in fact it will get MORE than proportionally worse. So for hunting, will try to stay in the best part of the graph (at this setting, would not bother filling the rifle past 1800PSI to avoid those rising groups, and stop shooting or a refill after 15 shots).
