Billy
8 Pointer
Posts: 188
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Post by Billy on Sept 30, 2010 20:30:25 GMT -5
With all the rain we're getting, I'm curious if anyone has any idea of the rain effect on trajectory. Specifically, a 250 XTP in a .50 with 68grs H4198 and short black MMP. I don't have a chronograph, but from other data on this board, I believe that to be about 2350 fps muzzle velocity. How much of a vertical impact to poi would a light rain have at 200 yards? I assume this is dependent on the heaviness of the rain, but assuming a light rain where you can still see your target at 200 yards. Would there be an impact, or would it not be noticeable? Billy
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Post by 12ptdroptine on Sept 30, 2010 20:37:09 GMT -5
Cant help but think it would have an effect... A few years back I shot at a nice 8pt from 40 yds with a 12ga deer slug... missed him totally! then I saw the tiny twig 5' in front of me moving..... I know that is what it was. Deflected it clear off the deer. However when he came back I blew the bottom of his heart off at a ranged 97yds. A fat raindrop has got to have some effect on it.
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Post by tdillinger on Sept 30, 2010 20:40:58 GMT -5
not worried, are loads arw water tight exclude barrel.
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Post by deadeye on Sept 30, 2010 22:02:04 GMT -5
no effect /not noticable//just keep your powder dry! btw send some of that rain to indiana if you would please ;D
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Post by wilmsmeyer on Oct 1, 2010 5:15:49 GMT -5
None that I've noticed. As said earlier just keep your powder dry with a barrel condom.
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Post by Richard on Oct 1, 2010 15:51:11 GMT -5
None what so ever! We have shot many a benchrest match at 600 and 1,000 yards in the rain with no effect on POI. Our only problem comes with visibility. If you can't see the target, you cannot hit it ;D. I actually shot two of my smallest 600 yard groups in a fairly steady rain this summer. I actually believe that the rapid rotation of the bullet and the air it pushes off the nose, create a "shield" so to speak. I would go so far as to say that water never touches the bullet in flight! Richard
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Post by rossman40 on Oct 1, 2010 16:51:53 GMT -5
Nothing to do with rotation, once the bullet goes supersonic there is a shockwave that will prevent rain from even touching the bullet. You missed the thread/discussion on fluid dynamics.
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Post by Rifleman on Oct 1, 2010 19:34:43 GMT -5
I agree with Richard and Rossman, shot too many matches in the rain to believe it has an effect on POI. However if one is using irons, then you may have to adjust to the difference in light that effects how one sees the target. However just because we know something, does not mean we have to tell it. It can be a handy excuse for a miss. It ranks right up there with the gravitational pull of the moon.
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Post by Richard on Oct 1, 2010 19:50:13 GMT -5
Rossman...........thanks for correcting my terminology! Thats why it is good we have you here Richard
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Post by ozark on Oct 1, 2010 19:55:06 GMT -5
Add me to the camp that says rain has no effect on trajectory. Like Rifleman, I have shot many competitive matches in rain and no compenstion was needed. Foul weather can effect the shooter. Shooting 20 rounds in twenty minutes at 600 yards (part of the National Match course) in sub zero tempatures or freezing rain can test your intestional fortitude. The angle of falling raindrops can act as a good wind indicator. I used to love deer hunting in the rain because it covers any noise one makes moving.
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Billy
8 Pointer
Posts: 188
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Post by Billy on Oct 1, 2010 20:47:04 GMT -5
Great information! Thank you all very much. Billy
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Post by deadon on Oct 1, 2010 20:47:12 GMT -5
That bullet never gets wet
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Post by rossman40 on Oct 1, 2010 21:41:03 GMT -5
The "M" in front of the number is the Mach number or the speed of sound in the first photo. 2559fps in the second photo comes out to about Mach 2.35. The speed of sound is roughly 1100fps. Where this becomes important in shooting is when the bullet slows down and goes from supersonic to subsonic the shockwave moves from in front to behind the bullet and can tumble the bullet. Short fat bullets take it better then long pointy ones. Also your drag coefficient or BC goes south during this period. Here is Laupa's radar data,
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