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> Two reasons: it's too quiet on the forum....
Two reasons: it's too quiet on the forum....
@ 09:16 am (GMT) |
Paul Leverman.....and I feel like starting something.I was playing with some ballistic charts, seeing what my "cheat sheets" may end up looking like. Did the usual velocity ups and downs, ranges, etc. Took the MOA adjustments required for whatever distance and superimposed them on the reticle to see what it would look like. Like I said, just playing. Then I added the standart 10mph wind at 90* to see what it would look like. The numbers weren't all that bad to my way of thinking, and I recalled someone once saying that the 7mm bullet was a superior wind cheater over the 30 cal. Well, let's just have a look, shall we? Temperature, barometric pressure, humidity, and altitude were standardized for these exemplars. 7mm (.284") 1:9" Twist 162gr ELD-M 3050fps Wind drift (10mph @ 90*) @ 1000 yards = 4.68MOA 30 (.308") 1:10" Twist 225gr. ELD-M 3050fps Wind drift (10mph @ 90*) @ 1000 yards = 4.29MOA That's a difference of 4.08" @ 1000 yards. I'm just guessing that on any animal from deer-sized and up, that four inches (the width of your hand) isn't going to make any difference to the wound channel. Is the 7mm really that much superior? You'll have a hard time convincing me. |
Replies
@ 10:50 am (GMT) |
Willy BartelRe: Two reasons: it's too quiet on the forum....Hi Paul,Your comparison is not very apples to apples. There's a giant gap in SD and not many cartridges that can launch that giant 225gr pill SD .339 at the velocity you used for an example. If you compare Nosler Reload Data(which I find is often optimistic) The 7Rem Mag and anything bigger can launch a 162 to 168 gr bullet at 3050 while even a 30-378 Weatherby doesn't break 3000fps with a 220gr custom competition. Apples to apples would be more like a 190gr ABLR with identical sectional density or 195gr ELD-M which can be launched from a 300Win Mag at almost the same speed as you're using for your example. Try comparing the 7 Rem Mag to 300 Win Mag with bullets of the same SD or the 28 Nosler vs 30 Nosler. A better comparison would be the new 180gr ELD-M SD .319 could be launched by a 28 Nosler at 3050fps or faster vs the 208gr ELD-M SD .313 out of the 30 Nosler at just over 3000fps. The new 7mm 180gr ELD-M which can be launched at 3050 by production cartridges would only drift 3.77 MOA at 1000yds vs the 4.29 MOA of your (theoretical) example. Thanks for posting...making this reply was a fun way to relax after a long hike this morning. |
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@ 05:07 pm (GMT) |
Paul LevermanRe: Two reasons: it's too quiet on the forum....Hi Willy. Good points, but related to specific chamberings. I wasn't really wanting to compare cartridges, but more so ballistic comparisons.I haven't tried the newer 195 ELD-M, but I have used the 190gr BTSP of old as a fireforming projectile. The twenty rounds went from a low of 3161fps to a high of 3207fps. These were without crimping and seated at .020". Just a generic stiff load to form brass. With the 208gr I've hit max loads with 4831 and 7828 at 3328fps and 3323fps, respectively, and 3311fps with 4350. I only picked 3050fps because it was a common velocity to both the bullet weights, and what I thought would be a common hunting load. So I took the liberty of using the 180gr ELD-M @ 3050fps and comparing it to the 225gr, and the difference between these two was only 5.6" @ 1000 yds. Again, and just to stir the pot, what's so special about the 7's? It's only .5MOA difference. |
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