Thread: Accuracy at 100 vs 600 (example). Variations in accuracy at different ranges

Lot of techno talk here,just practice head shots on rabbits out to 300yds will kill any deer out to 500yds with my 308.

I once owned a Rem model 7 in 308 that shot 1 3/4 to 2 inch at 100 yds and 3 to 4 inch groups at 500 yds not all 100 yd groups pan out at longer ranges.

Originally Posted by Terminator

I once owned a Rem model 7 in 308 that shot 1 3/4 to 2 inch at 100 yds and 3 to 4 inch groups at 500 yds not all 100 yd groups pan out at longer ranges.

that just prooves out what we have been saying...at 500 yards you HAVE to get your shite together and concentrate on technique and presise aiming...at 100 yards I believe we all get a bit slack at times.

I spent a little time on the Trentham range some years back, and I believe bullets do 'wake up' and 'go to sleep'.

A chap I was talking to had 3 different 308 loads for his shooting - all with the same cases, powder, and projectiles, with different amounts of powder. I asked why he didn't just use one 'best' load.

He told me that he used different loads so that he could choose when/where on the bullets flight the bullet would hit the second sound barrier. When it hit that the bullet would oscillate around the point of aim, and then settle back onto the central line. So paradoxically he might use a less powerful load when moving back from 600m to 800m - it was all about avoiding the bullet reaching the target while 'awake'.

I thought this a bit odd, but Din Collings confirmed the theory to me, and for me he was an authority to be believed, having won the Ballinger Belt once or twice.

That's my 2 cents worth. Not my theory - someone else's, but that guy was drilling the bull at 800m with open sights, and did it on a regular basis.

Not something I have bothered worrying about given my distances are 200m or less..........

No body has been able to prove this happens yet. Even when Litz tried it and offered to pay others for the proof. Still no one has been able to.

Originally Posted by blair993

No body has been able to prove this happens yet. Even when Litz tried it and offered to pay others for the proof. Still no one has been able to.

Yep I agree! Wheres the science.
In saying that there are lots of people reckon the same thing!

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Wouldn't there be too many variables in an outside location i.e wind, pressure, humidity, altitude and of course the shooter, to conclusively prove this theory exists?

Originally Posted by 243wssm

I spent a little time on the Trentham range some years back, and I believe bullets do 'wake up' and 'go to sleep'.

A chap I was talking to had 3 different 308 loads for his shooting - all with the same cases, powder, and projectiles, with different amounts of powder. I asked why he didn't just use one 'best' load.

He told me that he used different loads so that he could choose when/where on the bullets flight the bullet would hit the second sound barrier. When it hit that the bullet would oscillate around the point of aim, and then settle back onto the central line. So paradoxically he might use a less powerful load when moving back from 600m to 800m - it was all about avoiding the bullet reaching the target while 'awake'.

I thought this a bit odd, but Din Collings confirmed the theory to me, and for me he was an authority to be believed, having won the Ballinger Belt once or twice.

That's my 2 cents worth. Not my theory - someone else's, but that guy was drilling the bull at 800m with open sights, and did it on a regular basis.

Not something I have bothered worrying about given my distances are 200m or less..........

I know that when the bullets "pop through the sound barrier as they drop from super sonic to sub sonic, then the pressure around them induces a wobble and they "re-stabilise" into a steady trajectory afterwards. However the wobble affects their direction of travel and the steady subsonic trajectory may not be where you aimed. Easiest way I can describe this is think of a dinghy with a motor pushing it along. Motor is locked into straight ahead and the water is dead flat boat travels in a straight line. then it hits the wake of another boat (representing the disruption of going trans sonic) and induces a wobble. When the water is flat again the boat steadies into a straight line but now is pointing in a new direction and will continue that way.

For the situation above I can think of a few reasons for the different loads that are not "tuning" per se. To push the speed up high enough that that it stays above super sonic speeds at longer ranges uses more powder and more recoil. For example, to get 200fps increase at the muzzle (which pushes the drop through the sound barrier another 150yds out) on my 303 with a 175gr pill takes it from a minimum ADI load to just over maximum recommended load. (43gr 2209 increases to 48, or 38gr up to 43gr of 2208)

I dont need the extra velocity so I use a medium load.

Originally Posted by ChrisW

Its not possible. A projectile cannot just alter its course mid flight (other than due to external factors, wind etc), as would be required in order for a projectile that was shooting say 1 inch at 100 to shoot better than that at distance.

I would respectfully disagree. Projectiles may not get more accurate at distance, but they can certainly get less accurate. In the military, different calibre sniper rifles have different ranges they are guaranteed to make a headshot on, due to the different ranges that projectiles with different bc's and weights drop back through the sound barrier, as described above.

Also, many years ago for shits and giggles I would reload tracer projectiles out of 556 rounds into my trusty 222. With tracer burnout around 800m it was obvious that the 1:14 twist was not effective at stabilising long projectiles, as the tracer would arc gracefully out to 300ish, then scribe a weird helix about 50m dia till tracer burnout occured. Quite impressive to watch.

Originally Posted by 243wssm

He told me that he used different loads so that he could choose when/where on the bullets flight the bullet would hit the second sound barrier.

What second sound barrier?

Originally Posted by veitnamcam

I personally tend to shoot better groups at 200m vs 100m(moa wise) but I think that is more of a eye strain /lighting/parallax type issue.

I'm the same. Can be useless at 100m sometimes

Originally Posted by vulcannz

What second sound barrier?

I believe he's referring to the fact that a bullet, once sent on its way will break the sound barrier somewhere along the length of the barrel whilst being accelerated by expanding propellant gases, then as drag from the atmosphere slows the projectile down, somewhere down range the projectile will pass back through the sound barrier a second time.

That doesn't make sense, it's still the first sound barrier. Might've been easier to say "when the bullet goes subsonic".

If you have a fence in front of you, and you hop over it... you hopped over the first fence. You don't turn around and hop back the other and say "I hopped over the second fence"

I think what is meant is the disruption as the bullet starts to go trans sonic and then a further disruption at fully subsonic. It is not just and exact line to cross, more like a DMZ

Originally Posted by blair993

No body has been able to prove this happens yet. Even when Litz tried it and offered to pay others for the proof. Still no one has been able to.

It was actually proved / demonstrated by a Doctor in the USA around 1880 - 1900.