Originally Posted by AJ Peacock
Interesting read indeed.
What do you consider accurate at 2 miles? What would be considered inaccurate?
Well... that's a loaded question! What is accurate at 1,000 yds?
20" groups? How about 10" groups?? OK, how about 5" groups???
I'm long in the tooth enough to remember then Louise DeVito broke the 10 inch "barrier" at 1,000 yds, at Williamsport PA... with a worlds shattering record of 7" (point something) group, and no one could believe it. In fact, back not that many years ago, most people didn't believe you could shoot 20" groups at 1,000 yds.
Now... the 1,000 yard record is well under 2". So was Louise's rifle accurate (it set a world record), or is it a piece of junk, cuz it's isn't even in the running?
So what is accurate at 2 miles?
When Skip Talbot was alive, he ran a shooting barbecue at his place a few times a year for 50 BMG shooters, and the target "de jour" was a boulder that was not too big - at 2,700 yards. Over the years, the boulder was torn to shreds... is that accurate? I mean a boulder? How about a chipmunk at 2,700 yds. What is accurate?
There is no such thing as a definition of "accurate", because it keeps morphing as we get better, we build better rifles, we make better barrels, we make better bullets, and we understand (and can measure) atmospherics better.
It appears that their accuracy is on the order of around 10ft of their target with repeated attempts. Thats around 3moa+, however if its 10ft left, 10ft right etc, then its more like 6moa+ unless I miss understood something (it is late).
I don't think they shot a "group" that day... they were dialing in on a Prairie Dog, the same way a PD shooter would at 1,000 with a .22-250, or .243 - correcting for the wind by chasing puffs of dust.
But if we use 10 feet as an example, that 3 MOA at 3,500 yds.
Would you stand there? Not this fool - I may be dumb, but I'm not stupid!
Keep in mind that there is 10 seconds of flight time, and much of that time, the bullet is well over 100 feet above the ground, and flying through the air... so unless a day is picked that has "0" wind, the actual grouping capability is not evident.
But the reason I put that link there is that the bullets sure as hell aren't tumbling. At 2 miles, and 3 MOA, they are still more accurate (in moa) than a lot of hunting rifles that come over the counter are, at 100 yds.
It appears that if 1000 yard groups are hitting at 1/2MOA, that something is happening out there when the bullet drops out of supersonic to go from 1/2MOA to 6moa+?
A CLASSICAL mistake in analysis of a shooting problem... the assumption that "... something is happening out there when the bullet drops out of supersonic to go from 1/2MOA to 6moa+?"
Let me translate your logical error into the arena that is more familiar to the average shooter. How's this for an example?
It appears that if 100 yard groups are hitting at 0.10" MOA, that something is happening out there when the bullet drops out of supersonic to go from 0.1 moa to 2 moa at 1,000 yds?
This example would be fitting to a .22-250... yes?
But lets take the same example to another cartridge.
It appears that if 100 yard groups are hitting at 0.10" MOA, that something is happening out there to the bullet when the groups are going from 0.3 moa at 100 yds to 1.5 moa at 1,000 yds? WITHOUT GOING SUBSONIC!!
What the hell happened to the bullet - this is a 300 Win Mag, and this scenario is NOT unrealistic.
A lot of stuff happens to bullets as they fly, and the more time they are flying around in the atmosphere, the more bad stuff happens to them.
It is not logical to automatically attribute ANY of this to "subsonic" events, unless you can document them.
If these things are subsonic caused, then you should be able to duplicate them at ANY range where the bullet passes from supersonic to subsonic... a .22 Hornet at 400yds... but you can't!!
So there goes that theory, up in smoke.
There is the belief that there is some kinda "Trans sonic zone" that is filled with turbulence, that tosses and tumbles bullets well off their track.
As an experiment sometime, get a .308 or 30-06 and a box of tracers. Go off with a friend and a spotting scope. Have your friend shoot at something faaaar off, even if it's just the side of a mountain... and watch the tracers through the scope - they go "subsonic" at 700 to 800 yds.
I have done this - so should you!
As you watch those glowing bits of fire fly across the sky, what you will NOT SEE, is any deviation in path or flight characteristics, as the bullet "transcends the terrible trans-sonic wall" that is so frequently mentioned by those that know nothing about it.
There are many other issues in long range bullet flight, and when you get waaay out there some of these come into play... the most common is lack of rotational stability. It is simply the fact that as bullets slow down in forward speed, their rotational speed also slows down, though not in direct proportion... and at some point, they are just not spinning fast enough to stay point first.
A 12" twist has been the standard twist for the 308... and in some cases, shooters of the 308 at 1,000 yds complained of bullets tumbling at 1,000 yds.
It was automatically assumed that it was the dreaded "trans-sonic turbulence zone" booger men that were getting the bullets... but, a switch to 10" twist stopped the problem... so what happened to the "trans-sonic turbulent zone" - it was not the problem in the first place.
Funny... the thousands and thousands of match shooters that used 30-06 rifles for 50" years prior to the 308, NEVER complained about tumbling bullets - how come??
Because the 30-06 has ALWAYS had a 10" twist!!
It is Sooooooo tempting for people to "grab" onto an explanation that seems to explain a problem, if they are not trained to look at those kinds of problems - mankind has done it since the dark ages (think back to the "science" of astronomy of the years of 1400 AD).
I have a good friend that I teach radio with.
His name is Mark Spencer.
He is a TOP military pilot for U-2 spy plains and B-2 bombers. He was "the" adviser to General Schwarzkopf during Desert Storm.
He has spent more time supersonic, than ALL of you guys have spent shooting, put together.
His bonafides are here, read them - he is a VERY interesting man:
Town of Newington, CT - NARL Program: new approach to teaching basic electronics
About the presenter
ARRLWeb: WA8SME is New Coordinator of ARRL's "The Big Project"
The U-2 in Desert Storm Chapter 6 Desert Storm
Now... the point of this is, I asked Mark about the dreaded "Trans-sonic zone", in relation to shooting and bullets, and he laughed.
A summary of what he said was... most civilians get their idea of supersonic flight from movies from the 60's. The "wall" or "Barrier" was from the design of the planes, not the sound barrier - there is no such thing. The problems with the planes of the time, was that the wings were designed for lift and not speed, so they were thick, REALLY THICK. Also, a lot of equipment was placed in the wings, like cannons and 50 cal machine guns, with the large boxes of belted ammunition.
When the plane went to and over the speed of sound, the air molecules could not smoothly flow over the thick wings in time to get out of the way of the next bunch of molecules, so they jammed up on top of themselves, and caused the wing to vibrate.
The second problem was that the elevator tail control surfaces were on the rear end of the tail, and the air flow characteristics of the tail above the sound of speed, meant that the air didn't return to the control surfaces in time for the elevators to have proper effect - the pilots of the time didn't understand this (no one did), so they called it "The sound barrier"... but when engineers got hold of it, and started using wind tunnels, they easily solved this problem by using the whole tail as an elevator.
The third problem was the wings were at 90° to the fuselage, and weren't braced for the loads that the high speed airflow caused.
So the planes shook at high speed.
When flying a current designed plane, there is NO change in the plane as it goes past the speed of sound - if you are accelerating, you feel the slightest change in G forces pushing you into the seat, because the "rate of change" in speed changes... but you have to be looking hard to feel it, because it is so small... there is no shaking or any other effect, except that you see the fuel consumption gauge show a 3x increase in pounds per second.
So that's Mark's comments on the "Trans-sonic zone" BS. I'll take his opinion over some yahoo at the shooting range.
For Curtis "Hell divers" in WW-II, it was a real problem, but for bullets, it does NOT exist.
There is no "trans-sonic" turbulence that causes bullets to tumble - it is a wives tale.
Every time someone rants about the "trans-sonic turbulence" effecting bullets... there are lots of folks out there that are laughing - they don't say anything, cuz they are tired of the arguments (as am I), but the giggles are there, just the same.