extended ballistics - federal .308M
assuming you mean 7.62x51, and assuming you would be using a bullet suited to long range use, below see an excerpt from:
Maj. John L. Plaster, USAR (Ret.), an overqualified author on this subject.....
as you can see, windage gets kinda tricky past 600 yds, even if one has a wind meter, it will not always be doing the same thing at an over 1/3rd mile away target...one needs to be able to judge wind by plant movement, dust flying, etc.
experienced operators only need apply beyond this. this is the basis for my 600yd max-effective limit, not an inability for the round to kill WAY beyond that.
Federal .308 Match, 168 Gr. BTHP
FEDERAL .308 168-Gr. BT HP Match, Velocity in Ft-per-sec., Energy in Ft-Lbs.
Muzzle 100 200 300 400 500 600 700 800 900 1000
VELOCITY 2600 2420 2240 2070 1910 1760 1610 1480 1360 1260 1170
ENERGY 2520 2180 1870 1600 1355 1150 970 815 690 590 510
SIMPLIFIED UP/DOWN DATA
100-Yard Distance
Angle Compensation
30 Degrees 0.3"
45 Degrees 0.7"
60 Degrees 1.3" {Maximum effect}
So that you can see how to translate this up/down data into 1/4 Minute of Angle scope adjustments, we've included Table Seven, which shows these computations for a 45 Degree Slope.
Minutes of Angle Up/Down Compensation, 45 Degrees
Federal .308 Match, 168 Gr. BTHP Shooting Up -or- Down Compensation
Degree Slope hold-under in inches @ 100yd increments
100 200 300 400 500 600 700 800 900 1000
5 Degrees .01 .04 .10 .20 .33 .51 .74 1.0 1.4 1.8
10 Degrees .04 .16 .40 .75 1.2 1.9 2.7 3.9 5.2 6.9
15 Degrees .09 .38 .91 1.7 2.8 4.3 6.3 8.7 12 16
20 Degrees .16 .67 1.6 3.0 5.0 7.7 11 15 21 28
25 Degrees .25 1.0 2.5 4.7 7.8 12 17 24 33 43
30 Degrees .30 1.5 3.5 6.7 11 17 25 34 47 62
35 Degrees .48 2.0 4.8 9.0 15 23 33 47 63 84
40 Degrees .62 2.6 6.3 12 19 30 43 60 82 108
45 Degrees .70 3.3 7.8 15 24 37 54 75 102 135
50 Degrees .90 4.0 9.6 18 30 46 66 92 125 165
55 Degrees 1.1 4.8 11 21 35 54 79 110 149 197
60 Degrees 1.3 5.6 13 25 41 64 92 128 174 232
Yards/Compensation in inches/MOAs/1/4 MOA Clicks
100 0.7” 0.70 3 (0.74 MOA)
200 3.3” 1.65 7(1.75 MOA)
300 7.8” 2.60 10 (2.50 MOA)
400 15.0” 3.75 15 (3.75 MOA)
500 24.0” 4.80 19 (4.75 MOA)
600 37.0” 6.10 24 (6.00 MOA)
700 54.0” 7.70 31 (7.75 MOA)
800 75.0” 9.37 37 (9.25 MOA)
900 102” 11.30 45 (11.25 MOA)
1000 135” 13.50 54 (13-50 MOA)
REMEMBER: Always compensate by aiming LOW!
WIND DRIFT DATA for Federal .308, 168 Gr. BTHP Match
Deflection of a Crosswind 90 Degrees to Bullet Path in inches. {Use 3/4 of measurement for non perpendicular winds.}
100 200 300 400 500 600 700 800 900 1000
5 mph 0.4 1.5 3.7 6.8 11.1 16.1 23.5 32.0 42.1 53.8
10 mph 0.8 3.1 7.4 13.6 22.2 33.3 47.1 64.1 84.2 107
15 mph 1.2 4.6 11.1 20.4 33.3 49.9 70.6 96.1 126 161
20 mph 1.6 6.2 14.8 27.2 44.4 66.6 94.2 128 168 215
30 mph 2.4 9.3 22.2 40.8 66.6 99.9 141 192 253 322
MOVING TARGET LEADS, .308 Federal Match 168 Gr. BTHP
Distance in Yards/Lead in Inches
Target Speed 100 200 300 400 500 600 700 800 900 1000
Walk 3 MPH 7 13 21 29 37 46 56 68 80 93
Trot 6 MPH 13 26 42 57 74 92 113 135 158 185
Dash 10 MPH 21 44 68 95 122 154 187 224 264 306
The easiest way to remember the 3 MPH moving target leads is to COUNT IN SEVENS -- 7, 14, 21, 28, 35, 42 and you'll have the correct walking leads almost perfectly for 100, 200, 300, 400, 500 and even 600 yards.
Rifles & Shooting
EXTENDED BALLISTIC DATA FOR THE FEDERAL .308 MATCH ROUND:
All the data you wanted but couldn't find -- wind, moving targets, trajectories, etc.
By Maj. John L. Plaster, USAR (Ret.)
After nearly a decade of instructing police and military students in counter-sniping and precision shooting, I've amassed a useful variety of .308 Match ballistic data, which has been further refined and developed for inclusion in a new textbook, "The Ultimate Sniper: An Advanced Training Manual for Police and Military Snipers."
The most thorough book ever written on sniping and long-range scoped rifle shooting, it also contains extended data on Federal .223 Match, .300 Winchester Magnum; 7.62mm military Match; .243 Winchester; and even the .50 Caliber Browning rounds.
Because this .308 Match data is of great interest to NTOA riflemen -- and such a wide variety has never before appeared in print -- my publisher, Paladin Press, has authorized me to share it with you.
Although derived from ballistic tables provided the author by Federal Cartridge Co., many of these results required such additional calculation that I alone must take responsibility for accuracy. While these calculations were meticulously performed, I still recommend that you verify the results in your own rifle before attempting a 'real-world' shot.
The Trajectory Table
The accompanying trajectory table (Table one) tracks this round for any zero distance from 100 through 1000 yards. While few law enforcement riflemen zero their weapons beyond 100 yards, I'd rather risk giving you too much information than not enough. (Some tactical missions, such as skyjacks, of course, may require a more distant zero.)
Still, even if you zero for just 100 yards, you should know the exact bullet trajectory so you'll see how high to 'hold' for a longer range shot, if it proves necessary.
Moving Target Data and Compensation
Normally it's much better to wait and engage your target when he pauses momentarily rather than attempt a moving target shot. But a moving target may be the only shot you've got.
All the data published in Table Three reflects a target moving 90 degrees to the path of your bullet, that is, moving directly right or left, which is FULL VALUE. Should the target move oblique right or left, whether toward or away from you, use ONE HALF the value since in relative terms he's crossing your front at half the speed. And when he's heading directly toward you or away from you, there's NO VALUE and no movement compensation or leads at all. Aim dead-on.
Must you actually carry all this data in your head? No. I memorize just the 3 MPH leads, then double them for a trotting target and triple them if it's at a dead run. And I can mentally cut in half any one of these if the target's moving obliquely.
The easiest way to remember the 3 MPH moving target leads is to COUNT IN SEVENS -- 7, 14, 21, 28, 35, 42 and you'll have the correct walking leads almost perfectly for 100, 200, 300, 400, 500 and even 600 yards.
Crosswind Data
The best reaction to a stiff crosswind is to shift your location so you're either perfectly upwind or downwind from your target and thereby eliminate the effect of wind altogether.
When relocating is physically or tactically unfeasible, the Wind Data in Table Four allows great accuracy when properly applied.
And don't forget that unlike a moving target, an oblique wind is NOT 1/2 value but 3/4 value since a bullet is very sensitive to a crosswind.
Must you actually carry all this data in your head? No. I memorize just the 3 MPH leads, then double them for a trotting target and triple them if it's at a dead run. And I can mentally cut in half any one of these if the target's moving obliquely.
The easiest way to remember the 3 MPH moving target leads is to COUNT IN SEVENS -- 7, 14, 21, 28, 35, 42 and you'll have the correct walking leads almost perfectly for 100, 200, 300, 400, 500 and even 600 yards.
Up/Down Shooting Compensation
While the book explains this phenomenon in depth, just let it be said here that up/down shooting requires aiming LOW for compensation. Despite it not seeming logical, this is equally true whether your target is downhill or uphill; always compensate by AIMING LOW.
Keep in mind how quickly angles increase as a suspect's position gets higher above street-level -- by the time he's about 4 - 5 stories or higher, and you're across an average downtown street, he's probably already 40 degrees UP. The Austin 'Texas Tower' gunman, Charles Whitman, fired from a 28-story perch about 50 degrees UP from most-lawmen, who typically returned fire from cover 300 yards away. This means their uncompensated shots probably hit about ten inches high and helps explain why it took so long to neutralize him.
We computed this data for UP/Down angles at 5 through 60 degrees in Table Five, just so you could get a better feel for the effect. (Sixty degrees is the angle at which the greatest compensation is required.)
To keep from dazzling you with too much complicated up/down information, I've included "Simplified UP/DOWN Data' (Table Six) which shows the compensation needed at 100 yards for 30-, 45- and 60-degree up/down targets. You can see that there's little compensation required at such short range until the angle approaches 60 degrees, and even then you need only aim 1.3 inches LOW to be perfectly on-target.
hope this helps,
gunnie