Ballistics Question - .223 horizontal distance?


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Ironbarr
January 2, 2003, 11:48 PM
Info needed for site selection.

Data: AR-15 16", Win Q3131A (5.56 55g), Muzzle height 5'-1" off ground, Field length = Infinite, Field lay = Flat, Wind = 0, Temp = Cool to Mild, Weather = Clear & Dry.

AR is presented parallel with surface. When fired, how far will the bullet travel before meeting the field surface???

-Andy

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Tom A
January 3, 2003, 01:21 AM
I don't have exact specs for Q3131A, but to put you in the ballpark, my ballistics charts for Sierra HPBT 55 gr. show a drop of about 60" at ranges of 440 yards (3000 fps) to 470 yards (3200 fps).

Steve Smith
January 3, 2003, 12:32 PM
I don't have any charts or programs, but I think Tom's info is correct. My comp rifles start with a 200 yard zero and I add a total of 12 minutes (72") elevation to get to the 600 zero. Of course, the first zero is for 77 SMK, and the second is for 80 SMK.

Zak Smith
January 3, 2003, 02:44 PM
Here's some data. Not sure if this is exactly the right BC, though. Drag model is G1.

_BC_ _MV_ 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 | YARDS
0.260 3000 > -0.00 -0.12 -0.51 -1.17 -2.13 -3.41 -5.02 -7.00 -9.25 -12.00 -15.20 -18.88 -23.07 -27.80 -33.13 -38.82 -45.45 -52.81 -60.98 -70.02 -79.54 | > SA M193 55gr
0.260 3100 > -0.00 -0.12 -0.48 -1.10 -1.99 -3.19 -4.69 -6.54 -8.64 -11.21 -14.19 -17.62 -21.51 -25.92 -30.87 -36.16 -42.31 -49.15 -56.72 -65.09 -74.33 | > SA M193 55gr
0.260 3200 > -0.00 -0.11 -0.45 -1.03 -1.87 -2.99 -4.40 -6.12 -8.09 -10.49 -13.28 -16.48 -20.12 -24.23 -28.85 -33.78 -39.51 -45.87 -52.91 -60.69 -69.26 | > SA M193 55gr
0.260 3300 > -0.00 -0.10 -0.42 -0.97 -1.76 -2.81 -4.13 -5.75 -7.60 -9.85 -12.46 -15.46 -18.87 -22.71 -27.03 -31.64 -36.99 -42.92 -49.49 -56.74 -64.72 | > SA M193 55gr


Hope this helps.

-z

TCW
January 3, 2003, 05:02 PM
Doesn't a .223 rise in height for the first 100/200 yds?

Zak Smith
January 3, 2003, 05:07 PM
I assumed Ironbarr was asking about what would happen if the barrel were parallel to the surface, regardless of the sight-in distance.

If you want data for it sighted in at some range, I can run that, too.

-z

Nero Steptoe
January 3, 2003, 06:34 PM
With the barrel parallel to the ground, per the question asked, the .223, as well as any other bullet, will begin to fall below the line-of-sight of the muzzle the instant the bullet exits the barrel.

Ironbarr
January 3, 2003, 07:59 PM
Interesting information, for sure- and I thank you all for your interest and replies... and digging out that data.

Why I've asked is that I have access to the described field - except that is is not "infinite" - it is an odometer-measured 9/10-mile long, an estimated 400yards wide (rectangle) with a county road crossing along one end. There are drainage ditches on three sides. Looking from one end to the county road end, there are interferences on one side (houses facing away toward another road beyond).

As most of my latest posts TFL & here) show, I'm recently into the AR-15 world. With reading, et al, I'd understood that trajectory was rather flat at the FPS of typical .223/5.56 rounds. I was concerned that popping off at a 4-legged rascal or crow, etc. would carry too far if a miss.

By your replies I see that there's roughly a 400-500 yard window (unless the sights were set high or muzzle elevated). I see that I left out the sight setting data, sorry for that.

I'm still in the break-in rounds and haven't yet gotten serious about zeroing, though I know it shoots left - with elevation right close at 25-yard range.

Any helpful info appreciated.

Thanks.

-Andy

Zak Smith
January 3, 2003, 08:29 PM
Keeping in mind the 4 safety rules, here's data for the rifle sighted in at 200 yards:


_BC_ _MV_ 0 200 400 600 800 1000 | YARDS
0.260 3000 > -2.44 -0.01 -24.47 -97.48 -257.91 -553.25 | > SA M193 55gr
0.260 3100 > -2.44 -0.01 -22.55 -89.87 -238.52 -515.96 | > SA M193 55gr
0.260 3200 > -2.44 -0.00 -20.84 -83.08 -220.92 -481.49 | > SA M193 55gr
0.260 3300 > -2.44 -0.00 -19.31 -77.01 -204.98 -449.69 | > SA M193 55gr



This assumes bore to sight-plane distance of 2.5", which should be about right on an AR.

Keep in mind that this load (BC 0.260, MV 3200 fps) will be able to travel VERY far. I calculate that at around 31 degrees inclination, it'll travel approx 3570 yards. That's two miles.

-z

JohnKSa
January 3, 2003, 09:18 PM
Be very careful. Just because a bullet hits the ground doesn't mean it comes to a stop--it could ricochet back up and travel for another mile or more.

You really shouldn't shoot unless you can verify that there is nothing for around 2.5 miles downrange that can be damaged or injured or there is some sort of natural backstop which will likely aborb misses.

okeydoke
January 3, 2003, 09:56 PM
charts in the loading manuals, plug in a 40 gr or 50 gr plain based sp, at 3600 or 3300 fps, and you will see that they are both as feeable at 1000 yds as a .25 ACP is at the muzzle, and at 1500 yds, they are essentially harmless. Once something as fragile as a 223 sp hits the ground, it will be so damaged, keyholing, yawing, etc, that it is most unlikely to travel another 1/4 mile, with enough energy left to be dangerous. At ranges under 300 yds, if the 40-50 gr varmint hp's and sp's hit the ground, or hit a crow, they fragment right there. The concerns you have are for a military fmj or heavy, boattailed match bullet, fired at 39 degrees upward from horizontal. Then it MIGHT still have BB gun type "power" left at 2.5 miles.

Ironbarr
April 21, 2004, 12:36 AM
While searching my start-up threads I find that I have a mea culpa here - forgetting to thank you for your replies and great information.

So, humbly, I beg your pardon.

And - thank you.

-Andy

voilsb
April 21, 2004, 12:49 AM
My ballistics program says that the M193 round (3100fps MV from a 16" barrel, 55gr FMJBT with a 0.243 BC), when zeroed at 1 yard (effectively having the barrel parallel to the ground) drops 61.8 inches after 460 yards.

30Cal
April 21, 2004, 11:59 AM
Be very careful. Just because a bullet hits the ground doesn't mean it comes to a stop--it could ricochet back up and travel for another mile or more.

If you fire 3 times I'd be surprised if 2 of the rounds didn't ricochet.

Ty

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