Gain additional velocity by shooting prone ...

[adam32]

It cannot EVER be proven unless you have ammo with an ES/SD of ZERO! Which is impossible. You can chart things out and see a possible "trend" but unless it's 100% reliable and CONSISTENT then the data is null and void.

Lead sled, multiple chronys, remote trigger, etc is what's needed for the test to be even somewhat plausible in my eyes.

I definitely love the spaceship comment...but don't tell NASA or they will spend a few billion bucks trying to figure out how to make the Earth lighter!

 

[MudRunner2005]

Sorry MR, that's just factually false. The "equal and opposite" reaction begins the split second the powder is touched off.

I saw an interesting demonstration years ago where they suspended a rifle by wires and fired it electronically comparing true recoil forces between braked and unbraked rifles. It was shot in slow motion with extremely high speed cameras and provided very good demonstration of the principle.

This is how it was determined experimentally that roughly 70% of recoil is due to the "rocket motor effect" with the remainder being simply due to the shifting mass. It's also the reason things like spring loaded recoil buffers and mercury recoil reducers actually work.

If any of you really wanted to prove this for yourselves you could compare velocities for equal loads using something like a lead sled vs a rifle allowed to free recoil on a slide.

Not trying to argue with you, but I have seen WAY too many super high-speed slow-mo's of bullets leaving the muzzle before any noticeable (with the eye) recoil starts. That leads me to believe that the bullet leaves the barrel before any pressure on the recoil pad could cause any affect on the bullet's performance. ALSO, I used to shoot free-recoil groups at the range, and had the exact same POI as when I shouldered up and held it tight on bags and it never moved backwards, just popped the barrel upwards from lack of rearward movement.

I would love to test it and prove it, but I don't own a lead-sled...Or a super slow-mo (250,000 FPS) camera. There's a guy on YouTube from Alabama named Destin. He has a channel called Smarter Everyday. He has all this equipment and does things like this with guns all the time. It would be really cool to get someone like him (unbiased) to test this theory.

Here's his YT channel if someone wants to contact him... If anyone can do this experiment completely unbiased, it would be him. I'm wiling to accept the results either way. If I'm wrong, I'm wrong, wouldn't be the first time...Won't be the last.

http://www.youtube.com/user/destinws2

 

[CJS-6.5]

I guess in my way of thinking, this is a long range hunting forum. So we practice for hunting as we would shoot hunting. Know your rifle. Ammo. Scope. Drop charts. Windage. Shoot the same every time. What we are looking at here in this thread is inconsistent shooting. Which has no place in long range hunting. It was funny for awhile but get real guys.

 

[J E Custom]

That's great !! All we have to do to get magnum performance is to shoot everything from the prone position.

Now I will have to try and test this theory. If i get the same results i will post it. Don,t see how it makes any difference like Mud said, because the bullet has left before there is any rifle movement.

"BUT" this would also mean that a muzzle brake can add velocity to your rifle.

If he is jetting a different velocity, I would think it has more to do with the Doppler signal coming back (Reflecting) differently at ground level than bench level. I have seen velocities changed from muzzle blast with and without a blast shield in front of the screens of a chronograph.

So I will try it with a Magneto Speed, where the first thing the chronograph sees is the bullet.

I personally wont believe it until I see it.

Just Me

J E CUSTOM

 

[FEENIX]

That's great !! All we have to do to get magnum performance is to shoot everything from the prone position.

Now I will have to try and test this theory. If i get the same results i will post it. Don,t see how it makes any difference like Mud said, because the bullet has left before there is any rifle movement.

"BUT" this would also mean that a muzzle brake can add velocity to your rifle.

If he is jetting a different velocity, I would think it has more to do with the Doppler signal coming back (Reflecting) differently at ground level than bench level. I have seen velocities changed from muzzle blast with and without a blast shield in front of the screens of a chronograph.

So I will try it with a Magneto Speed, where the first thing the chronograph sees is the bullet.

I personally wont believe it until I see it.

Just Me

J E CUSTOM

I was hoping someone would try to validate the claim. Looking forward to it.

 

[dfanonymous]

Edited, after rereading post

 

[gohring3006]

I think a good test would be eliminating the human factor.
Using a solid wall, like a block wall and using a rifle just lying in the bags with no one behind it. It doesn't have to be a nice rifle, but one that's getting low ES.

 

[barleydog]

You'd have to tear apart every shooting position there is to split all the hairs on this conundrum, don't think this rabbit hole has a bottom

im not sure that could have been more well put....

 

[J E Custom]

I can't believe I am commenting on this before I try to test this "theory"
But some interesting comments have came from it.

I prefer the practical application to any problem or theory.
The equal and opposite reaction is true and not theory, "But" Equal is the catch 22. The average rifle weighs 8 pounds (56,000 grains) plus the mass of the shooter. A 150 grain bullet is many times lighter. (To early to do the math before coffee) The bullet velocity will be many, many times faster than the rifle velocity and the shooters shoulder in the opposite direction. So in reality the rifle doesn't move/recoil measurably before the bullet will exits the barrel. (This is the reason
a muzzle brake must have .005 to .010 thousandths clearance all round for the bullet to pass through without touching anything.
I have never tried less than .005 thousandths for clearance so I realy cant say if it moves at all before the bullet exits.

So if we get less than 1 or 2 thousandths movement of the rifle, it doesn't make sense that velocity would change in any position. And I am not willing to restrain a rifle by placing it against a brick wall and firing it to find out.

If there is a difference in velocity, why would it not change from a lead sled to a shoulder shot. The Magneto Speed would be perfect for this test because it attaches to the rifle and moves with it.

I still think it is from ground effects from shock waves effecting the chronograph Just like the shock wave off the ground/floor that shows up in this video.

https://www.longrangehunting.com/threads/bullet-shock-wave.211219/

It is interesting to talk about this theory, but I just cant believe that the position can effect velocity that much if any.

J E CUSTOM

 

[Edd]

I once read a comment by BartB posted on this website that he had seen as much as 50 fps difference in velocity from changing nothing but the shooter.

 

[adam32]

I once read a comment by BartB posted on this website that he had seen as much as 50 fps difference in velocity from changing nothing but the shooter.

That's because the other shooter pulled the trigger harder.

 

[GeorgeS]

My comments on the YouTube page: <start> Don't understand the confusion below about a simple matter of momentum. Recoil begins at the moment the trigger is pulled. The hammer moving forward causes the rifle to move backwards, imperceptibly. The moment of the explosion, as the pressure builds in the cartridge, the powder in front of it starts moving forward, pushing the rifle backwards. Every action produces a reaction - it's fundamental physics.

If the collective resisting force is in any way different - the firmness of the grip, etc. - the motion of the rifle will be different. Recoil is underway the entire time the bullet is being accelerated down the barrel, moving the rifle backwards. It's more noticeable when the bullet leaves the barrel because of the rearward thrust imposed by the gases in the barrel being freed to accelerate to a much higher velocity than the bullet.

When you are sitting, the resistive moment of the torso is the weight of the upper body pivoting about the hips; when leaning forward, the resistive moment of the torso is that weight plus the force required to lift the torso to a right angle with the angle of thrust of the rifle. That's exactly the principle behind the delay imposed on blowback by a toggle action like the Luger. Each of these motions moves the butt of the rifle, changing the bore axis alignment. When prone, the resistive force is the weight of the entire body aligned axially with the bore of the rifle. (and the position of the recoil pad - against muscle tissue or against bone - ed)

These different resistive forces change the motion of the rifle both backwards and axially. Whether that motion difference can be accounted for by a chronograph, given the intrinsic shot-shot variation from cartridge to cartridge is the question. I assume that the muzzle velocities that (you) are reporting are a mean value of a string of shots, rather than a single difference, because 20 f/s is well within natural variability from slight differences in bullet weight, neck tension, seating depth, powder charge, powder position, primer activity, etc.

It would be helpful to the understanding of those commenting below if you had also included the number of shots and the standard deviation of each string. But it is easy to believe that a prone position would provide more resistance to backward motion of the rifle, resulting in a slightly higher muzzle velocity. <end comment>

My suspicion is that the velocity difference is real, caused by the higher resistance to the backward motion of the gun in the prone position. I'm less convinced that the change in point of impact is the result of that velocity difference. It's more likely the result of the motion of the shoulder up (when leaning forward) or down (when sitting upright) than the velocity difference.

 

[tbrice23]

I was hoping someone would try to validate the claim. Looking forward to it.

Trouble maker. lol.

You are worse than me,
if anyone at the range asks me what my chronograph is I tell them it's a turbo booster... then I wait for it.

 

[J E Custom]

Some of this post should be in the humor section

The up side is that I learned a new word. Sheeple (I like it)

J E CUSTOM