[Unclenick]

The trick is matching the powder to the bullet weight. The heavier the bullet, the better it will play with slow powders. I like the 4064 range of powders, and Varget was originally designed by ADI (as AR2208) to compete with 4064. With the 175-ish-grain bullet weights, the 4064s and Varget do very well. If you are going to shoot 125s and 150s, you may well discover your gun is happier with N135 or, sometimes, even with 3031. All you can do is try it.


Regarding the wind debate, the fishtailing wind simulated in the article isn't shifting 3°. The article says the standard deviation of the fishtailing is 3°. So the total error span for twenty shots will average 11°. Hence the bigger error.

You can use Didion's old formula from 1858 as an approximation. The sine of 11° is 0.19 on my calculator times 5 mph is 0.954 mph, times 1.46666… gives 1.399 ft/s, times 12, gives 16.8 inches per second for the span of the shift in crosswind velocity component. It's more precise to do ±5.5°, but at these angles, the error is less than half a percent, so I took the shortcut. If the bullet leaves the muzzle at 2800 fps, the vacuum TOF flight would be 3000 ft / 2800 fps, or 1.07 seconds. If the bullet has the equivalent of a G1 BC of 0.5 all the way to 1000, then the TOF in an ICAO standard atmosphere is 1.598 s (from an exterior ballistics calculator I wrote; cheating, but the only other way is measurement and Didion would have had a stepped sequence of ballistic pendulum measurements for this). The difference will be 0.528 s. Multiply that times 16.8 inches per second, and you get 8.704 inches of total shift in the horizontal plane. My ballistics software puts it at 8.69 to 8.91 inches, depending on if it is a tailwind or a headwind, but Didion's estimate still does pretty well for its age.