David - I use JBM Ballistics, which is an online calculator, but almost any ballistic calculator will give similar, if not exact, outputs. According to JBM, a 155 Hybrid (G7 BC = 0.245) launched at 3000 fps would experience wind deflection of approximately 3.8 and 7.4 MOA in a full value 10 mph wind at 600 and 1000 yd, respectively. A 200.20X (G7 BC = 0.328) launched at 2650 fps has a predicted wind deflection at those distances of approximately 3.3 and 6.1 MOA. If you increase the velocity of the 200.20X to 2725 fps, the predicted wind deflection shows a small decrease to values of 3.1 and 5.8 MOA at 600 and 1000 yd, or ~0.2 and 0.3 MOA less than the bullet launched at 2650 fps.
We typically use the wind deflection values for a full-value 10 mph wind as a standard for discussion and comparative purposes. However, even inexperienced shooters can usually make a wind call to much finer increment than 10 mph. So someone with good wind reading skills can probably make a wind call to 2 to 3 mph, whereas a mediocre wind call might be within 5 mph accuracy. Using those values, the realistic differences in predicted wind deflection values between the two 200.20X loads at 2650 and 2725 fps are tiny, less than 0.1 MOA and ~0.1 MOA at 600 and 1000 yd, respectively. Those differences are so small it would be very difficult to ever state with any certainty that the extra velocity (and therefore increased resistance to wind deflection) had any effect on scores. A difference that small could easily be due to slightly better precision of the load itself, or merely the innate group dispersion at a given distance, which is probably about 5-10 times larger than the difference in wind deflection of the two loads.
In contrast, you can see that the much higher BC of the 200.20X bullet produces significantly smaller predicted wind deflection than the 155s, even though they enjoy a 350 fps velocity advantage in this scenario. As I mentioned previously, it is rare to find a situation where velocity will ever trump BC. More often than not, pushing the lighter bullet with lower BC fast enough to overcome any BC deficit will push a load to pressures that will kill the brass primer pockets prematurely, or might even be unsafe.
Obviously, there are many additional important considerations that go into the equation. As you noted, targets with the smaller X-ring will require a load with excellent precision, as well as good wind reading skills, in order to obtain good scores with high X-counts. So maybe for a load I would use with that target setup, I would try to scratch out that last little bit of precision that I could. To that end, choice of bullet/powder, velocity, primers, just about everything becomes important.
It's also important to note that not all "accuracy nodes" are equal. Some are simply better than others, and those are the ones we typically try to hit with a given barrel length/bullet/powder combination. Sometimes, a slightly slower velocity node can give better precision, at the expense of a small amount of wind deflection. At shorter distances (300 to 600 yd), the slower velocity usually has less of an effect and the enhanced precision more than offsets it. Sometimes, the next higher node is the clear winner in terms of both precision and wind deflection. However, that sometimes comes at the cost of increased recoil and gun handling issues, as well as reduced brass life.
So, the bottom line is that none of this reloading stuff is written in stone. There is usually a choice of different approaches that can all work, each with its own unique considerations and caveats. It is up to the individual to choose the approach that suits them best. I have found over the years that I personally am much better off practicing regularly and trying to improve my wind reading skills, than trying to get a little more juice by pushing a load much harder. It all comes down to your past experience and shooting philosophy, there really is no "right" or "wrong" about it.
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