Hi Stick. I'm not trying to knock the 7 Mag. But I think your figures are off a bit.
<br> Here's why. Those BC's, I believe, are suspect. Rick Jamison, while working with the 7 Ultra, found the BC's for the Barnes XCL 140's, and 160's to be as much as .080 off.
<br> Extrapolating, the 120 gr. XBT's BC comes out to about .331, not .411. The 160 gr. BT I used in the following calculations is the Sierra BT soft point. I used the figure for velocities 2800 fps. and under, .470. My computer program can't handle their velocity variation figures.
<br> So, the 120 gr. XBT @ 3500 fps., with a maximum Point Blank Range of 3 inches is -3 at 319 yds. -11 @ 400 yds., -27 @ 500 yds., and -50 @ 600 yds. Wind drift, with a 10 mph crosswind is: 319 yds. 8, 400 is 13.5, 500 is 22 and 600 is 34. BTW, this is very close to the .308 175 gr. Federal match load. Recoil, out of a 9 lb. rifle is 12 fps. , and 20.5 ft. lbs.
<br> The 160 gr. SRA BT @ 3100 is -3 at 298 yds. , -14 at 400 yds., -31 @ 500 yds. and -56 @ 600 yds. Wind drift is 6 @ 298 yds., 11 @ 400 yds., 17 @ 500, and 26 @ 600 yds. Recoil., out of a 9 lb. rifle is 12 fps. ,and 23.1 lbs.
<br> What's it all mean ? Well, using a target style long range system, your pretty close to one MOA, or click, off. On elevation, as well as windage. Recoil is favored by the light bullet load. Energy by the heavy bullet load.
<br> As always, the big difference is bullet quality. I'll bet money the 120 Barnes XBT will out penetrate the 160 gr. SRA BT. Particularly up close. No comparison. This is based on lots of experience with the 140 gr. Nosler Partitions, and SRA's 140 gr. offerings.
<br> I've got some 120 Barnes XBT's loaded for my .280. When I get the chance, I plan to visit my local tactical range and see if I can tell just how close these figures are.
<br> I suspect you and I both know that computer generated tables are fine, if fed the correct information. I can verify that the Sierra figures are accurate for their 175 gr. MatchKings at .308 velocities. I don't know about the others. E
