You have to know the bullet's "time of flight", and for that, you have to know its starting velocity, the range, and the BC of the bullet.  You also have to know the speed of the moving target, and the angle of the target (relative to the shooter).  What all this adds up to is that you miss moving men a lot beyond 400 yds, especially if they are moving across your front.  Such a man is a sideways target for you (ie, 9" wide) and all you can do is guess his speed of movement.

Then you also have to allow for wind, mirage, up and downhill angles, plus you won't have a sandbagged bench to fire from.  Night scopes are very hard pressed to provide enough accuracy for reliable hits on stationary torsos at more than 1/4 mile.

For instance, let's say that you start a 168 gr hpbt .308 bullet at 2600 fps in your 22" barreled M1A.  That's a pretty hot load for an autorifle, by the way.  This bullet has a BC of .480. It will be down to 1750 fps at a mere 500 yds.  It has lost 850 fps in 500 yds of travel.  The average speed of the bullet is thus 2175 fps (as a rule of thumb only, but close enough for such "short" shots).  500 yds is 1500 feet, so the bullet's time of flight will be (approx) 3/4 second.  A man can easily change his speed of walking, stop, bend over, etc, in 3/4 second.  That can happen between the time you fire and the time your 308 bullet reaches 500 yds, and you won't be able to do a thing about it. Thus, if such a change occurs, your shot will miss the man.

Naturally, you'll need a rangefinder laser, and a windspeed meter, and a lot of practice at such shooting (which almost nobody gets, on movers).   At 1000 yds, the problems for the sniper (for getting a first rd hit) are a lot more than 2x as bad, because the bullet will have slowed down a lot more, and wind, mirage, and up and down hill angles will mean more. In fact, at  1000 yds, elevation above sea level, temperature, relative humidity, barometric pressure, and the tendency of a spinning bullet to "offset" a bit all become likely to cause a miss of a realistically man sized target (ie, 12" x 24").

Now, say the guy is moving at a rate of 3 mph, which is approx 4.5 fps.  3/4 of 4.5 is 3.3 ft. What does 3 ft of lead look like, at  500 yds, on your particular target? what if he's moving at 2.5 mph, or 3.5 mph? Either way, you'll have to change your lead, or miss the guy.  How can you gauge his speed of walking, that closely, at such a range?  Sure, mildot scopes are a help, but the odds of your missing a sideways man are still pretty high,

Have you any practice at all on moving targets at such distances? You'll have to shoot a 6" group out there, on a stationary target, to have a hope of hitting a man who is sideways to you, walking across your front.  Without a nice black and white bullseye (of the right size) windflags, spotter shots, and a sandbagged bench rest, this shot is probably going to miss. Then the survivors will be dodging as they seek cover, and you have no hope of being able to hit them as they do so.  At 500 yds, a head bobbing around cover is a nearly impossible mark, for any man with any rifle, under field conditions.

So now you've started something that you probably can't finish (by firing at too great a range). You won't have choppers to come evac you, or air strikes to smash the enemy for you.  Who, if shtf, is going to have the time and ammo to waste on such shooting, anyway? Sure, snipers will be a threat, but not at anything like the ranges guys fantasize about.   Only fools will be stationary targets, in open country, in daylight.

No, the VC that Hathcock and his spotter engaged (100+ of them) were not experienced soldiers. They were raw conscripts from the villages, except for a couple of officers and NCO'S.  If they'd known to hide until dark, and then dodge as they fled away from Carlos, they'd nearly all  have escaped unscathed. A bolt action is not much help at hitting multiple, dodging men, especially at night, and Nam era nightscopes only had about  300m of range (with any reliability of hitting a moving man). No, a sniper can't reliably accomplish anything like what the shtf dreamers think that he can.   A few fluke hits mean nothing.  It's what you can nearly always do, upon demand, in any sort of weather or conditions that matters.

Can you make a call to the artillery boys?

Quoted: Can you make a call to the artillery boys?

+1.  IMHO, under combat conditions you're just not going to make effective hits on moving personnel at more than 100-150 yards without a crew-served weapon.

Practice.

Quoted: Practice.

+1
+87
+87 x 87

Grew up practicing on Jack rabbitts while running around the desert with a remington pump action 22LR

excelent post

Full-Auto and just draw a line across his butt

Load every other round with a tracer to see the trail!

Quoted: Load every other round with a tracer to see the trail!

+1

Don't lead women and children as much.

Practice all you want, it just aint humanly possible. It's like running a 3 minute mile. You can try til you turn blue, you'll still never do it, except by luck.  Tracers aint that accurate, nor do they stay with the regular ammo all that well.  They are to help you get CLOSE, with a belt fed, and that's all that they can do.  Shtf, you aint gonna have either a belt fed or artillery. You will be extremely lucky just to have a spotter (who is worth having along).

When I was 19, I did a guy in Laos with a rifle shot at a thousand yards in high wind. Maybe eight or even ten guys in the world could have made that shot. It's the only thing I was ever good at...