Wind drift?

[michael_aos]

The more I've been shooting my .223 bolt-gun, the more I notice the wind is ALWAYS blowing when I want to shoot.

I've just started handloading the Sierra 69gr HPBT MatchKing in my 700P (1:9 twist) and I'm hoping to see some improvement over the 45gr "Varmint" and 55gr mil-spec ammo I've been shooting.

I still suspect it's never going to be as good as a .260 Remington though. And of course its an excuse for a new gun...

How do the two compare though? If the .260 is only 10% better, or "marginally" better in say a 10-15mph wind at 400yds then I can't really justify it.

I know I'm not shooting anywhere near the capability of this gun in general right now. On a calm day I'm sure it can shoot much better than I can (yet). Just don't want to be at a HUGE disadvantage when its windy.

Mike

[Religious Shooter]

The drift at 10 mph at 90 degrees (full value wind) with max velocities with Accurate Powder (you can eek out more velocity with a different powder):

.223

69 SMK (2903 fps) 10.3" @ 300 yards ; 49.5" @ 600 yards

80 SMK (2752 fps) 8" @ 300 yards ; 36.2" @ 600 yards

.243 Winchester

107 SMK (2965 fps) 5.6" @ 300 yards; 24.7" @ 600 yards

6mm REMINGTON

107 SMK (3068 fps) 5.3" @ 300 yards; 23.5" @ 600 yards

7mm-08 (.284)

150 SMK (2738 fps) 7.9" @ 300 yards; 35.6" @ 600 yards

168 SMK (2598 fps) 7.2" @ 300 yards; 32.1" @ 600 yards

.260 Remington

142 SMK (2742 fps) 5.6" @ 300 yards; 24.6" @ 600 yards

.308 Winchester

168 SMK (2714 fps) 7.3" @ 300 yards; 32.8" @ 600 yards

Roughly you are talking about 46% less drift at 300 yards when using the 142 SMK .260 vs. the 69 SMK .223. 50% less at 600 yards.

Other than the .223 above, the listed cartridges were based on the .308 case and the listed cartridges are supposed to be compatible (or at least tunable) for the AICS .308 mag.

I've been mulling this over and from the threads you actually need power to knock down or activate the targets. It looks like .260 Remington is the best all around choice that works with the .308 mags.

I'm going to be somewhat of a copycat and now plan to get a 700 in .308... shoot the bejebus out of it (practice and matches)... and then rebarrel it for .260... and get the AICS 1.75 with mags and HV scope somewhere along the way.

It looks like this the safe recipe for MOR.

[Zak Smith]

Here's a spreadsheet I worked up to compare both wind drift and drop at 800 yards.

http://www.demigod.org/~zak/tmp/ballistics.html