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Old June 14, 2000, 01:17 PM   #1
Mike H
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Guys,

I need a ballistics expert to help me out with a work related "debate" that arose after one of my co-workers spouted facts from a novel (of all things) that bullet drop at 2000 yards with an unspecified sniper rifle was over 100 feet.

I can't find any ballistic tables for shots out beyond 1500 yards, so the question is this, what is the approximate bullet drop at 2000 yards using standard weight and load match ammo for the follwing calibers :

.308 Win
.300 Win Mag
.338 Lapua
.50 BMG

If you can help me make my point here I'd be grateful,

Regards,

Mike H
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Old June 14, 2000, 01:28 PM   #2
Coinneach
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100 feet sounds extreme for anything hotter than .22LR. Remember though that the ballistic curve is in a decreasing radius, so it's not as simple as "If I hold 12" over at 300 yards, then I have to hold 24" over at 600." Essentially, the downward curve gets tighter as distance increases and velocity decreases.

I'll see what I can dig up.
------------------
OK, here we go.

Assuming sea level, standard conditions, I've come up with the following. .308, .338, and .300 are extrapolations based on a polynomial trendline. I did the work in Excel 2000; anyone who wants to see the numbers and charts, email me.

.308 Win
165gr bullet
2600 fps muzzle velocity
.481 drag coefficient
Approximate drop @ 2000 yards = 2850 inches, or 237.5 feet.

.300 Win Mag
165gr bullet
3000 fps muzzle velocity
.456 drag coefficient
Approximate drop @ 2000 yards = 2850 inches, or 237.5 feet (again).

.338 Lapua
200gr bullet
3000 fps muzzle velocity
.437 drag coefficient
Approximate drop @ 2000 yards = 2200 inches, or 183.3 feet.

.50BMG Updated
750gr bullet
2800 fps muzzle velocity
1.07 drag coefficient
Approximate drop @ 2000 yards = 1399.6 inches, or 116.3 feet.
-----------------
Verdict:

.50BMG with a heavy, fast bullet. Hoorah!

QED. And don't make me do this again, dammit!


[This message has been edited by Coinneach (edited June 14, 2000).]
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Old June 14, 2000, 02:16 PM   #3
Mal H
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Mike, I'm not sure which side of the argument you're on. But 100' is really on the extremely low side for drop at 2000 yards.

Breaking out the old Sierra Infinity program, I got the following using the highest possible muzzle velocity listed:

.308 Win
155 gr., 2900 fps MV = 270' drop at 2000 yds.
168 MK, 2700, 311'

.300 Win Mag
155, 3300, 210'
168, 3200, 224'

.338 Win Mag (don't have data for Lapua)
215, 2900, 242'
300, 2500, 203'

Unfortunately I don't have data for the .50 BMG, but I think it would win, hands down, in the long range drop contest (least drop). The biggest factor is time of flight. That's why heavier bullets will sometimes win even at lower velocities. They are moving faster at the 2000 yd line than the lighter bullets so they get there sooner. Gravity being a constant (sort of), the bullet that takes the least amount of time to get there from here wins.

[added]
Checking .50 BMG data from Cartridges of the World and the using a Speer 647 gr FMJ at 2800 MV, I get a drop of 170'. We have a winner.

[This message has been edited by Mal H (edited June 14, 2000).]
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Old June 14, 2000, 02:27 PM   #4
Coinneach
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OK, we gots a controversy here. Art, whose numbers are better, mine or Mal's?
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Old June 14, 2000, 02:36 PM   #5
Mal H
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Actually, our figures are not all that far apart. They are within the infield of the same ball park. Different BC's will really make a big difference, I used mostly Sierra bullets and you might not have.

The one we obviously disagree on is the .50 BMG. Are you sure you can get 4000 fps out of one?
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Old June 14, 2000, 03:10 PM   #6
Coinneach
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Mal, I used Barnes X for my samples. Probably a different drag coefficient, yep.

As for the .50BMG velocity, 4000 is the highest I've seen for that weight. I'll plug 2800 in and see what happens.

[This message has been edited by Coinneach (edited June 14, 2000).]
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Old June 14, 2000, 04:13 PM   #7
Mike H
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Coinneach & Mal H,

I stand in absolute awe of you 2, jaw drop and not bullet drop was pretty severe reading your results believe me.

I will now have to go into work tomorrow and eat crow. Just how much crow ?, well, I estimated that a flat shooter like the superb .300 Win Mag would have maybe 8 feet of drop at 2000 yards ! Yes, I know, major error, seems the author of said book was actually on the low side for his 2000 yard "snipe", with his drop of just over 100 feet. My thanks again, and if you 2 theoretical mathmaticians want to continue this to an agreed resolution, rest assured I'll be watching closely,

Best,

Mike H
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Old June 14, 2000, 05:27 PM   #8
Art Eatman
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Gosh, coinneach, I can't even see a deer at 2,000 yards, much less guess the hold-over!

Somewhere around 500 yards, mine eyes glazeth over!

Art
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Old June 14, 2000, 05:40 PM   #9
James K
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Now you have to take into consideration the curvature of the earth which means the drop is actually greater than if the shooting were done on a plane surface... NO, DON'T HIT ME! I'LL GO QUIETLY!

Jim
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Old June 14, 2000, 05:51 PM   #10
Southla1
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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Jim Keenan:
Now you have to take into consideration the curvature of the earth [/quote]

Well lets see, if we take the curvature of the earth into account, that means that in theory the shooter is on the top of a hill and is shooting down, so lets see that means less drop etc. NO! NO ! DON'T HIT ME EITHER!!



------------------
Carlyle Hebert
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Old June 14, 2000, 06:41 PM   #11
HankL
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Man, at 2000 yds you have to take the rotationof the earth in to account!
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Old June 14, 2000, 06:48 PM   #12
Southla1
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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by HankL:
Man, at 2000 yds you have to take the rotationof the earth in to account![/quote]

True if you were shooting due East or West you would have to figure either more or less drop! North or South more drift? NO NO I agree with Art..Hell I have trouble seeing 50 yards lol.

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Old June 14, 2000, 07:17 PM   #13
STLRN
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At 2000 meters the 50 caliber, both M2 AP and M3 ball have a max ord or 25 meters, the drift is only 0.5 mils so about 1 meter of right drift at 2000 meters. Aproximately 2700 meters the Max ord is 66 meters.
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Old June 14, 2000, 07:33 PM   #14
WalterGAII
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Maybe in the novel, the guy had already sighted his rifle in (probably Bob Lee Swagger) for 1000 yds, which would be a more typical shot than 2000 yds. In that case, then perhaps 100 ft. might not be so far off.In other words, maybe he was only implying 100 feet after 1000 yds.
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Old June 14, 2000, 07:48 PM   #15
Josh D
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Just goes to show ya that Ol' Hathcock made one HELL of a shot with the M2 BMG

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Old June 15, 2000, 09:40 AM   #16
Ric
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The ultimate heavy might be the 14.5mm Soviet.

Plaster in "Ulimate Sniper" briefly discussed the 14.5 mm (994 gr AP at 3300 fps), used by the Afgans against the Russians in custom-built Pakistani bolt-action sniper rifes. Max effective range was about 2 miles (3,500 yds !). I wonder what optics they used?

BTW what are the TOF's and terminal vel for the .30 caliber rounds at 2000 yds ?


------------------
-ric
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Old June 15, 2000, 09:49 AM   #17
Hutch
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Holy Smokes!!!! 994gr at 3300fps!!! In a turnbolt??? I thought the .50BMG would be the ultimate experience. I'd like to see the boyo who'd touch that'un off in a homemade rifle. Great huge brass ones.
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Old June 15, 2000, 12:04 PM   #18
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You guys have us looking for a way to squeeze a 2000 yard range into the new location. We could do it, but we'd have to shut the rest of the underlying range down while the 2000 yarders are at it. At least they'd be shooting with the prevailing wind rather than across it. But they'd also have about 800 foot of elevation gain over that range. The backstop would only be maybe 100 feet high.
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Old June 15, 2000, 01:42 PM   #19
Mike H
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Well crow tastes bad, believe me, a small crowd gathered and statements such as "he's admitted he was wrong, never thought I'd live to see it" etc were uttered. For reference the novel featured a family who flew over a patch of desert in a light plane where someone had rigged up a range, and videoed what they saw. Subsequent examination by a "ballistics expert" revealed that the range had been specifically constructed to calculate the exact windage and elevation required for a single 2000 yard shot, this was determined as being just over 100 feet vertical drop.

I believe the British have a 2000 yard competition each year at the Bisley ranges, this is freqeuntly won by the humble .303 fired through an accurized Lee Enfield. As I recall they fire propped up on one side lying almost flat on their backs.

Mike H
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Old June 15, 2000, 03:25 PM   #20
Mal H
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Ric - here are the TOF, vel. and energy for the 168 Match Kings in both .308 cartridges (again from Sierra Infinity):

.308 Win
TOF = 5.19 sec.
Term. Vel = 746 fps
Term. Energy = 208 ft-lbs

.300 Win Mag
TOF = 4.49 sec.
Term. Vel = 803 fps
Term. Energy = 241 ft-lbs
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Old June 15, 2000, 05:26 PM   #21
Zach Vonler
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Aren't the .30 cartridges going to be useless at such a distance because they're going to have gone transonic at around 1000 yards or so? It's my understanding that when they do that the BC is no longer easily calculatable, and there's no reliable way to calculate drop from that point on. True?
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Old June 15, 2000, 05:47 PM   #22
Mal H
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Zach, you are absolutely correct. The BC will change as the velocity drops. This is why I like the Infinity program, it has built in the BC changes at 5 different velocity boundaries as the bullet moves along. Or you can plug in your own values, if you have better data (I don't).

For example, the 168 MK starts with a BC of .462 at the muzzle and drops to .405 at the 5th (slowest) boundary transition.

I don't think anyone is really planning to try 2000 yd shots, this was mostly an academic discussion so that Mike H could get his butt laughed at when he returned to work. (Eight foot drop! Lordy, lordy!)
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Old June 15, 2000, 06:27 PM   #23
STLRN
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Military 50 cal TOF to 2000 meters: 4.3 sec, terminal Vel: 297 m/s angle of fall 70 mils
Military 7.62 (non M852) 2000 meters TOF 6.54 seconds, angle of fall 166 mils, no data for terminal velocity
From FMFRP 6-15 Machine guns and Machine gunnery. Data obtained via Modified Point Mass Equation.
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Old June 16, 2000, 12:51 PM   #24
Eric of IN
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Sometimes I'm rendered speechless at the breadth of knowledge that is present on TFL. Within 1 1/2 hours Mike H had 2 answers with close to the same results.

I did have one question though, since the rifle is fired at a fairly steep upward angle, will the bullet maintain it's nose up attitude throughout the flight path, and impact the target somewhat sideways?
Eric

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Old June 16, 2000, 01:04 PM   #25
Mal H
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Wow, damn good question. I've never thought about that aspect. Will the bullet somewhat maintain it's initial orientation due to gyroscopic forces or does the aerodynamic effect take precedence? STLRN, Art?
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