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Advanced Marksmanship The effect of free recoil on POI

wadcutter

Sergeant
Full Member
Minuteman
Dec 23, 2008
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NSW Australia
www.austargets.com
I have been trying to validate the trajectory of a light weight .338 RUM out to 1000 yards or so in the field.
Seems that when I shoot this beast free recoil due to awkward shooting possitions, it shoots a bit higher than when I get my shoulder behind the stock properly.

Am I onto something here? or am I just imagining it?
 
Re: The effect of free recoil on POI

I doubt you're imagining it. As they always say, "believe the bullet". The effect of recoil on your POI, especially with a cartridge that recoils that much, can easily happen.

The real question is if it is repeatable and angular. Does it always impact "x" mil/moa/whatever each time? If so, then you can document and adjust for it in the future. If not, then it sounds like a marksmanship issue somewhere.
 
Re: The effect of free recoil on POI

there is no doubt recoil effects trajectory. that is why poeple talk about different zeroes for standing bench and prone and sitting, yada yada.

if you want a control put it in a lead sled, but personally i figure if i can't repeat it in the field im not too interested...
 
Re: The effect of free recoil on POI

You're not imagining the POI shift. Are you also blinking at the moment the rifle goes off?
 
Re: The effect of free recoil on POI

The relationship between line of bore at rest and line of bore at bullet exit must, by some method, be controlled so as to be a consistent relationship from shot to shot. Since this relationship is angular, any control inconsistency while the rifle is recoiling will mean some sort of novel recoil effect, resulting in unaccounted for angularity, an error which will increase with distance.

Free recoil is a concept which only works in limited scenarios, such as BR, with a very heavy rifle producing very light recoil. In the field it would be better to just establish contact with the gun which can be maintained. The factors of a steady position are elbows, grip, non-firing hand, stock-weld, and butt-to-shoulder.

Maintaining control of the rifle until recoil has subsided, is a concept, for many, which is as esoteric as it is apocalyptic. Folks have some knowledge that control is important; but, apparently, they do not recognize the extent of perfection required for the best result.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">Free recoil is a concept which only works in limited scenarios, such as BR, with a very heavy rifle producing very light recoil.</div></div>That doesn't explain why it works so well for 50 BMG's.
 
Re: The effect of free recoil on POI

The design of Barrett rifles and a few others promote rearward/forward recoil; and thus, divergent angularity from shot to shot is not the issue as it is with other action types. Also, weight and a muzzle brake help to maintain the users control over the rifle until recoil has subsided.
 
Re: The effect of free recoil on POI

Thanks for the advice.
I have tried to replicate the effect over the last few days and Yes it is repeatable and consistant.
When I get into a solid possition behind the stock and have some preload on the BiPod it is not a problem.
I guess I just need to work on my field shooting technique and practice more. With this rifle I need firm contact and follow through. Letting the rifle do its own thing just doesn't work.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wadcutter</div><div class="ubbcode-body">Thanks for the advice.
I have tried to replicate the effect over the last few days and Yes it is repeatable and consistant.
When I get into a solid possition behind the stock and have some preload on the BiPod it is not a problem.
I guess I just need to work on my field shooting technique and practice more. With this rifle I need firm contact and follow through. Letting the rifle do its own thing just doesn't work. </div></div>

I question the use of a rifle that just has its trigger pulled without anyone to shoulder it.

I see this on bench rifles, but thats a different story.
 
Re: The effect of free recoil on POI

One thing that I've found is, you have to drive the rifle. Especially the big magnums in a light weight rifle, which this one would qualify. I prefer to shoot prone, so I set everything up for that. I try to keep each shot the same- firm cheek pressure, straight behind the gun, trigger finger 90 degrees, bipod not loaded, good rear sandbag position, etc. Whatever your method, do it 100% of the time. It's hard to preload the bipod each time (due to different shooting locations), so I prefer not to load the bipod up when shooting. If you load the bipod, and sometimes do not load it up, this will definitly change up your POI. Just keep things consistant from shot to shot.
 
Re: The effect of free recoil on POI

I think with the guns we shoot in competition we've found that one of the most important things to the accuracy of our guns is maintaining the same everything for each shot. Same palm pressure against the grip, same finger pressure around the grip, same pressure rearward on our trigger, same pressure or lack of with our elbows, arms and shoulders for the follow thru.

Learning to feel when it feels right each and every time you line up for a shot takes a lot of disciplined shooting and being observant of what it felt like and what happened when it went off.

The way I shoot mine is not totally free recoil but the less pressures I apply and allow it to recoil naturally has made it shoot much better. This might not apply totally to a rifle shooter in various positions but the slightest pressures that vary between shots sure do affect bullet placement on a distant target.

I know what we do is different than what you rifle guys do in preparation for the shot but we all still have to be aware of what we do to prepare and also follow up after the shot.

Spending good quality time in practice by yourself and also another shooter that might be much better to offer tips will be one of your best ways to gain improvement in your skills.

It's so satisfying to see ones skill improve and hear more distant dings on steel as you get better.

Good luck but like others have said, it's not important to get into the equipment race right off. Buy the best you can afford, learn to shoot it well and move up as skill and funds allow.

Topstrap
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wadcutter</div><div class="ubbcode-body">I have been trying to validate the trajectory of a light weight .338 RUM out to 1000 yards or so in the field.
Seems that when I shoot this beast free recoil due to awkward shooting possitions, it shoots a bit higher than when I get my shoulder behind the stock properly.

Am I onto something here? or am I just imagining it?</div></div>

Trajectory is a definitive and uniform arc. Increase the attitude of the bore (line of departure) and the bullet will travel further, visualize a quarterback throwing a football. Hitting where aimed is kinda like throwing a football, adjusting the sights for an attitude that will get the bullet to the target distance. Thereafter, it's all about supporting sight alignment and trigger control.

What's important is to control the rifle consistently shot to shot from the time the trigger is pulled until recoil has ceased. The technique you use to get consistency, i.e. free recoil or other, must transfer the stability of the ground into the position though artificial and bone support. The elements of a steady position are NPA, muscular relaxation, and bone/artificial support. The factors describing the contact between the shooter, gun, and ground include: stock-weld, elbows, butt-to-shoulder, grip, and non-firing hand placement.

Be conscious for consistency, as without it, the angle created between the line of bore at rest and line of bore at bullet exit will be somewhat divergent shot to shot, which will produce angular error that increases with distance. That's to say, you may hit higher or lower, or for that matter, anywhere other than where aimed. This is what you are alluding to having recently experienced. I also gather you may be thinking about this as a method of aiming. If so, forget it.

BTW, forget the free recoil too. It will not produce the results desired for a multitude of reasons. Instead, learn how to build a steady prone position using a sandbag support.
 
Re: The effect of free recoil on POI

I'm going the opposite direction.

Through a bit of luck, I have seen with my own eyes high speed film of a bullet leaving the muzzle, and the bullet is long gone before the muzzle rises or a bolt/slide racks/moves in a semi-auto rifle, handgun, no question about it. It's gone before anything moves.

I have seen this 3 different times, with a bit of youtubing maybe people can find more examples or prove me wrong, I don't have an agenda either way, just the times I saw it the bullet was definitely clear before anything moved on the gun.

Shifts in POI when changing positions may be due more to parallax error, ie your eye is in a slightly different spot when you are standing vs. prone, etc.

I don't claim to know everything but I do think the above is worth considering and investigating. After I saw film I never worried about recoil again.
 
Re: The effect of free recoil on POI

I don't have any proof to show it either way but I can tell you that the types of guns I shoot and the distances I shoot them different tension on my grip definately do affect POI for me. The slightest difference in my grip really makes a difference the further out I shoot.

It's interesting to see and read about what you are saying but I can only go by what I've experienced with my guns. I know I'm passing along info that might not pertain to rifles since I'm not as experienced with them as I am the various types of handguns but I'd expect the same effect to be present by different pressures exerted by grip, cheek and shoulder pressure.

Will be anxious to see what others have found cause I'm always ready to be proved wrong and learn from others.

Topstrap
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Outerspace</div><div class="ubbcode-body">I'm going the opposite direction.

Through a bit of luck, I have seen with my own eyes high speed film of a bullet leaving the muzzle, and the bullet is long gone before the muzzle rises or a bolt/slide racks/moves in a semi-auto rifle, handgun, no question about it. It's gone before anything moves.

I have seen this 3 different times, with a bit of youtubing maybe people can find more examples or prove me wrong, I don't have an agenda either way, just the times I saw it the bullet was definitely clear before anything moved on the gun.

Shifts in POI when changing positions may be due more to parallax error, ie your eye is in a slightly different spot when you are standing vs. prone, etc.

I don't claim to know everything but I do think the above is worth considering and investigating. After I saw film I never worried about recoil again.</div></div>

Can you see fifteen thousandths of an inch? Recoil begins as the bullet begins to travel through the bore. Recoil creates an angle from line of bore at rest and line of bore at bullet exit. Divergence in this angle due to inconsistent control of the rifle from shot to shot leads to angular error which increases with distance. The position must be perfect, shot to shot, for zero displacement to be possible.
 
Re: The effect of free recoil on POI

I am a newbie, so take it or leave it...

but I first noticed how free recoil affects my shots when shooting my .308 from a bench. I noticed I could practically hit the same hole at 100 yards when I applied rearward pressure with my firing hand to lock the rifle to my shoulder. When I "limp wristed" my rifle off the bench, shots sprayed up to 2" groups at 100 yards.

My 2 cents.

BN
 
Re: The effect of free recoil on POI

What you can see is when recoil starts and when the slide or bolt begins to move, and it is quite a bit after when the bullet leaves the muzzle. It's unmistakable.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Outerspace</div><div class="ubbcode-body">What you can see is when recoil starts and when the slide or bolt begins to move, and it is quite a bit after when the bullet leaves the muzzle. It's unmistakable.
</div></div>

Recoil begins as soon as the bullet begins to move, period. Consistent control of the rifle until the bullet has cleared the bore is essential to good shooting. The idea is to continue to aim until recoil has subsided. This is known as follow-through. Follow-through permits the shooter to call the shot, that's to say, understand the target/sight relationship as the bullet exits the muzzle. Calling the shot, and ploting it, as well as the bullet strike makes shooter/target analysis possible.
 
Re: The effect of free recoil on POI

The muzzle is motionless, the slide/bolt is motionless until after the bullet is well out of the muzzle. The beginning of recoil or the bolt/slide moving doesn't start until after the bullet has left the muzzle, it is easy to see. I can only tell you what I've seen with my own eyes. Anyone can investigate for themselves if they want.
 
Re: The effect of free recoil on POI

I think you've lost this debate mr. outer-space man.....Newton said it best-"for every action, there is an equal and opposite reaction." it's just simple physics.
 
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Re: The effect of free recoil on POI

I've shot a gun where I literally pinched the trigger& rear trigger guard and let the gun to it's own recoil thing on bags, it wasn't in my shoulder and my face wasn't on the stock.


I was shooting pretty consistently .3-.5" center to center groups at 100 yards with my big heavy (17lbs) bench .22-250 this way, but I would still say this is an unsustainable/unpractical technique.

accurate, yes. practical, no. the gun was consistant in whatever it did shot to shot. Currently I am trying to attain the same consistency with the "loaded bipod/in-line-recoil method" I'm close with my 20" .308, but not quite there yet.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nostradumbass</div><div class="ubbcode-body">I think you've lost this debate mr. outer-space man.....Newton said it best-"for every action, there is an equal and opposite reaction." it's just simple physics. </div></div>
The thing is it isn't a debate, it's science and you can either demonstrate your position or not, it is not subject to debate. One can theorize all day long but never determine anything until you make observations or tests.

You can watch it for yourself and make up your own mind.

http://www.youtube.com/watch?v=-YdEGWEX4LM&feature=channel
http://www.youtube.com/watch?v=a2P0Wyoill4
1:20
http://www.youtube.com/watch?v=HaVhfQcqfGY&feature=related
3:05
http://www.youtube.com/watch?v=c0PmzI6BEzg

Detectable movement is less than any possible shaking by the shooter, the bullet is simply moving too fast.

After the bullet leaves there is still obviously high pressure in the barrel, and thanks to Newton's second law the compressed air pushing off the breach causes nearly 100% of the recoil movement despite the fact that bullet is gone.
 
Re: The effect of free recoil on POI

This may not be relevant to this subject but my shooting buddy Dale also shoots these long range handguns with me. He just had 3 different brakes made for his Savage Striker in 260 to experiment with. He's played with all 3 brakes and also without the brake shooting paper at 200 yards.

There is a definite difference in point of impact without and with the brake. There is also a subtle difference in a couple of the brakes but until he gets to our longer range to see how it affects it at extreme distances we can't be sure of how much it really is. If the bullet was out of the barrel before any reaction happened shouldn't the point of impact stayed the same no matter what was on the end of his barrel?

This is a gun that he uses for 1000 yard plate matches and he's quite a skilled shooter so any variation in bullet impact is the result of the changing of the brakes or leaving it off. He's very thorough in his testing but I agree with Sterling, it only takes a few thousandths rise to make an impact change at distance. The mount that I used on my gun can be set using a dial indicator and .001 is equal to 1 moa so it don't take much variation in movement to equate to a change in impact location.

I did watch Darby's video, The loads that him and other quick draw and also some other types of competition shooters use are very light loads compared to weight of the gun being used. It could be possible that the recoil is so light compared to the weight that it does not rise enough at the close distances they shoot to show a difference. There are a lot of factors to figure in that are way over my head in solving this. You try holding a Ruger SBH 44mag light one handed and then holding it tight with two hands and you'll not be hitting the same place on a target.

I think the same thing may be said for rifle shooters that sight in off a bench, then find they don't hit the same place from a prone, kneeling or standing positions. It can be done but takes a lot of practice to learn to apply same pressures for each position they shoot from.

All of this fascinates me, the more I shoot this long range stuff the more things I find come into play on making a good shot. I don't think at closer distances the POI is affected very much but stretch it out and the variations really become noticeable.

Topstrap
 
Re: The effect of free recoil on POI

The reality is that high speed footage is probably the only definitive answer, and if you don't have it you're in pure speculation land.

The really good video I saw I cannot find on youtube, yet, but it is even clearer.

I imagine that the load, weight of gun, length of barrel and probably more all factor in, but one would be making a mistake to be going off assumptions when it is probably mostly determinable.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Outerspace</div><div class="ubbcode-body">The reality is that high speed footage is probably the only definitive answer, and if you don't have it you're in pure speculation land.

The really good video I saw I cannot find on youtube, yet, but it is even clearer.

I imagine that the load, weight of gun, length of barrel and probably more all factor in, but one would be making a mistake to be going off assumptions when it is probably mostly determinable.</div></div>

What you see is deceiving you. Once the trigger is pulled, recoil begins to disturb the rifle bore at rest. This disturbance is immediate and progressive. Control of the rifle can make such disturbance however appear minuscule. Nevertheless, this disturbance is measurable, as well as observable.

What you've seen is movement of the rifle after the bullet has left the bore; and, obviously, movement then is not effecting accuracy. And, if the shooter had maintained consistent control of the rifle, while the bullet was still traveling though the bore accuracy would not be effected. This is because recoil is bound by the relationship between the shooter, gun, and ground.

Take an iron sighted rifle and you can see something that can only be seen from the shooter's perspective, something your observation has not shown. It should convince you that your observation has reached the wrong conclusion. Shoot the rifle from a steady support. Adjusting NPA, focusing on the front sight, and with the best follow through you can muster, you should be able to call your shots, that's to say, you should know exactly where the front sight was in relationship to the target as the bullet cleared the barrel. Change the position. You will see this changes your call. Why, because recoil is different. It has caused the bore to move someplace other than where it would have moved before altering the position. If recoil began, as you say you have seen, after the bullet had left the rifle, the aim would not have been disturbed and the bullet would still hit where aimed.

The big picture here is knowing what's important to good shooting. And, although I appreciate your pont of view, perhaps you might want to test your facts from what you've done, in addition to what you've seen.



 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">What you see is deceiving you. Once the trigger is pulled, recoil begins to disturb the rifle bore at rest. This disturbance is immediate and progressive. Control of the rifle can make such disturbance however appear minuscule. Nevertheless, this disturbance is measurable, as well as observable.

What you've seen is movement of the rifle after the bullet has left the bore; and, obviously, movement then is not effecting accuracy. And, if the shooter had maintained consistent control of the rifle, while the bullet was still traveling though the bore accuracy would not be effected. This is because recoil is bound by the relationship between the shooter, gun, and ground.

Take an iron sighted rifle and you can see something that can only be seen from the shooter's perspective, something your observation has not shown. It should convince you that your observation has reached the wrong conclusion. Shoot the rifle from a steady support. Adjusting NPA, focusing on the front sight, and with the best follow through you can muster, you should be able to call your shots, that's to say, you should know exactly where the front sight was in relationship to the target as the bullet cleared the barrel. Change the position. You will see this changes your call. Why, because recoil is different. It has caused the bore to move someplace other than where it would have moved before altering the position. If recoil began, as you say you have seen, after the bullet had left the rifle, the aim would not have been disturbed and the bullet would still hit where aimed.

The big picture here is knowing what's important to good shooting. And, although I appreciate your pont of view, perhaps you might want to test your facts from what you've done, in addition to what you've seen.</div></div>
The issue is simply that this is a measurable phenomenon. So far, the opposing side has only offered theory and no data. While I have provided some "data", in my judgement it does not support the opposition, I am supposed to believe in something I cannot see, when I can pretty much see what's going on.

That's not to say that I'm right. I may be wrong. I would just need to see data/observation.

Even if you are right, we need to know how much the muzzle does rise before it no longer effects the bullet, and I cannot find anybody supplying that information, or where I can go to find it. This is not a criticism and not meant to be provocative, I just have to give my honest assessment that the sum of the information I have seen indicates that the effect of recoil on POI is indeterminably small, possibly negligible even within the incredibly tight margins of long range shooting.

I have no axe to grind either way, I do not want to be wrong, but on an issue where the phenomenon can probably be determined, I would like to see it demonstrated.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Outerspace</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">What you see is deceiving you. Once the trigger is pulled, recoil begins to disturb the rifle bore at rest. This disturbance is immediate and progressive. Control of the rifle can make such disturbance however appear minuscule. Nevertheless, this disturbance is measurable, as well as observable.

What you've seen is movement of the rifle after the bullet has left the bore; and, obviously, movement then is not effecting accuracy. And, if the shooter had maintained consistent control of the rifle, while the bullet was still traveling though the bore accuracy would not be effected. This is because recoil is bound by the relationship between the shooter, gun, and ground.

Take an iron sighted rifle and you can see something that can only be seen from the shooter's perspective, something your observation has not shown. It should convince you that your observation has reached the wrong conclusion. Shoot the rifle from a steady support. Adjusting NPA, focusing on the front sight, and with the best follow through you can muster, you should be able to call your shots, that's to say, you should know exactly where the front sight was in relationship to the target as the bullet cleared the barrel. Change the position. You will see this changes your call. Why, because recoil is different. It has caused the bore to move someplace other than where it would have moved before altering the position. If recoil began, as you say you have seen, after the bullet had left the rifle, the aim would not have been disturbed and the bullet would still hit where aimed.

The big picture here is knowing what's important to good shooting. And, although I appreciate your point of view, perhaps you might want to test your facts from what you've done, in addition to what you've seen.</div></div>
The issue is simply that this is a measurable phenomenon. So far, the opposing side has only offered theory and no data. While I have provided some "data", in my judgement it does not support the opposition, I am supposed to believe in something I cannot see, when I can pretty much see what's going on.

That's not to say that I'm right. I may be wrong. I would just need to see data/observation.

Even if you are right, we need to know how much the muzzle does rise before it no longer effects the bullet, and I cannot find anybody supplying that information, or where I can go to find it. This is not a criticism and not meant to be provocative, I just have to give my honest assessment that the sum of the information I have seen indicates that the effect of recoil on POI is indeterminably small, possibly negligible even within the incredibly tight margins of long range shooting.

I have no axe to grind either way, I do not want to be wrong, but on an issue where the phenomenon can probably be determined, I would like to see it demonstrated.</div></div>

Dude, marksmanship is not esoteric or apocalyptic, the science of it is settled. Perhaps, you did not read or understand the third paragraph from my previous post. Its instruction shows you how you can observe movement produced by recoil, while the bullet is still traveling through the bore. One thing for sure, your pseudoscience is distracting you from good shooting. Oh, your comment, "we need to know how much the muzzle does rise before it no longer effects the bullet", I think "demonstrates" your ignorance of this topic in general. Even a miniscule divergence in angular movement, less than the thickness of a quarter, measured at the muzzle from line of bore at rest and line of bore at bullet exit, will cause a miss at any distance other than one where the target can be hit intuitively.
 
Re: The effect of free recoil on POI

I don't know.

In every other aspect of shooting I can measure everything in velocity, mass, energy or minutes of angle (or mils if you prefer).

In atmospherics I can measure temperature, atmospheric pressure, elevation, humidity, etc, predict by math formula the effect on bullet flight and then verify computation with actual shooting in real life.

So far no one has produced any way to measure the effect of recoil on flight or POI, so we are left with mystery meat.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Outerspace</div><div class="ubbcode-body">I don't know.

In every other aspect of shooting I can measure everything in velocity, mass, energy or minutes of angle (or mils if you prefer).

In atmospherics I can measure temperature, atmospheric pressure, elevation, humidity, etc, predict by math formula the effect on bullet flight and then verify computation with actual shooting in real life.

So far no one has produced any way to measure the effect of recoil on flight or POI, so we are left with mystery meat.</div></div>

Outerspace,

First, I think you're a neat guy, you're wonderin' and it's this sort of curiosity which has revealed the truth about many mysteries. But, in this matter the wondering of others has already revealed the truth, an understanding for the effect of divergent recoil, an effect which, at a distant target, is grossly measurable. This is why perfecting the relationship between the shooter, gun, and ground from shot to shot is so important when shooting at LR.
 
Re: The effect of free recoil on POI

Except that it isn't, because for any other aspect of shooting we can set up a chrono or take data by a variety or methods for a variety of variables and repeatedly predict the outcomes

In this case, not one person has produced one set of data, personally or from someone else of the measurable effect of recoil on ballistics.

This has been a data free discussion, except the crude data provided by me, which so far is all there is to go on.

Eg, someone might say "if I hold the gun this way instead of that way then my POI shifts x to the y", but so far there is no way to tell if the shift in POI is due to differing recoil effects or if the shooter has more or less flinch or other disturbance due to holding the gun differently.

If there is a way to tell I would be very happy to see it.
 
Re: The effect of free recoil on POI

If your rifle could talk it would tell you “leave me alone I’ll shoot the bullet” to a point.

Recoil starts at the moment the primer ignites. This process causes several things, yes the recoil and movement of the rifle as you all have been posting.

But it also starts the movement or flexing of the barrel and action, look at a rifle barrel in terms of a garden hose whipping or flexing as the pressure and bullet travel down the bore albeit a very small movement but that is all it takes (When the barrel does the same movement every time, this is a good thing). This is called the harmonic of the barrel and the main cause of cold bore and clean cold bore variations in POI due to the harmonic settling down into a consistent movement. Now you are driving your rifle and impart a different pressure on the cheek weld, shoulder mount, grip even trigger pressure this all affects this harmonic and will change it (even though a barrel is free floating), as well as the change in recoil movement you all have been posting about.

Bottom line here look at all things you impart on a rifle as MICRO-pressures, MICRO-body tensions, MICRO-movements....Get the idea small things matter with your <span style="font-weight: bold">consistency</span> to get the most <span style="font-weight: bold">accuracy</span> out of your rifle.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Outerspace</div><div class="ubbcode-body">Except that it isn't, because for any other aspect of shooting we can set up a chrono or take data by a variety or methods for a variety of variables and repeatedly predict the outcomes

In this case, not one person has produced one set of data, personally or from someone else of the measurable effect of recoil on ballistics.

This has been a data free discussion, except the crude data provided by me, which so far is all there is to go on.

Eg, someone might say "if I hold the gun this way instead of that way then my POI shifts x to the y", but so far there is no way to tell if the shift in POI is due to differing recoil effects or if the shooter has more or less flinch or other disturbance due to holding the gun differently.

If there is a way to tell I would be very happy to see it.</div></div>


There is a way, it's called shooter/target analysis.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">Free recoil is a concept which only works in limited scenarios, such as BR, with a very heavy rifle producing very light recoil.
</div></div>

The effect is the most pronounced in 22 and air rifle.

It's called an "artillery hold".
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KSwift</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">Free recoil is a concept which only works in limited scenarios, such as BR, with a very heavy rifle producing very light recoil.
</div></div>

The effect is the most pronounced in 22 and air rifle.

It's called an "artillery hold".</div></div>

As a concept or technique for accuracy in competitions free recoil is associated with BR, not smallbore, or air rifle events.
 
Re: The effect of free recoil on POI

If you are going to argue physics then you need to understand physics.

The question, obviously, is when does recoil begin....

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">While “recoil” is certainly related to Newton’s third law of motion that for every action there is an equal and opposite reaction, recoil is actually the phenomena which occurs when the expanding gas column which propels a projectile inside a cylinder suddenly clears the end of the cylinder and the gas rapidly expands, and it is this force that once it has transferred to the barrel causing it to move in the opposite direction which we call “recoil.” Therefore, it may be observed that a shorter barrel produces a far greater recoil than a does a longer barrel because the shorter barrel has less internal volume for the gas to expand and is thus under a greater pressure when it vents than does a longer barrel which because of its greater volume contains a lower pressure when it is vented (i.e. when the projectile clears the muzzle). Until this point, the internal expansion of the gas does not translate into any measureable motion within the barrel, and if any part of the explosive chain could be felt, depending on the relative mass of the barrel it would perhaps be the movement of the projectile's mass within the barrel affecting the equilibrium or balance of the barrel, but not causing or contributing to any kind of recoil force, least not until the projectile escapes from the cylinder. So it is the internal gas pressure at the moment it escapes and expands from the barrel rather than the mass of the projectile that equates to the force of the recoil. The weight (i.e. mass times gravity) of the projectile is but a small portion of the total recoil force. <span style="text-decoration: underline">Theoretically, if a barrel was long enough to compensate for the full volume of the gas pressure, the forward motion of the projectile would literally stop and there would be no recoil.</span></div></div>

If recoil began at the instant a bullet moves, and thus building from that point throughout the bullet's barrel time, then the mantra of barrel harmonics and OCW that many of us worship as gospel would be a mute point. Recoil then would negate anything worthwile regarding muzzle ocillation and the "nodes" would be indistinguishable on paper. 'Course, there's a lot of folks that can't figure out OCW and barrel harmonics either......
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Topstrap</div><div class="ubbcode-body">I wonder if Jamie and Adam from Mythbusters read this forum?

Topstrap </div></div>

I hope not, cause they would F*$% it up like they do every other gun test they try...
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">If you are going to argue physics then you need to understand physics.

The question, obviously, is when does recoil begin....

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">While “recoil” is certainly related to Newton’s third law of motion that for every action there is an equal and opposite reaction, recoil is actually the phenomena which occurs when the expanding gas column which propels a projectile inside a cylinder suddenly clears the end of the cylinder and the gas rapidly expands, and it is this force that once it has transferred to the barrel causing it to move in the opposite direction which we call “recoil.” Therefore, it may be observed that a shorter barrel produces a far greater recoil than a does a longer barrel because the shorter barrel has less internal volume for the gas to expand and is thus under a greater pressure when it vents than does a longer barrel which because of its greater volume contains a lower pressure when it is vented (i.e. when the projectile clears the muzzle). Until this point, the internal expansion of the gas does not translate into any measureable motion within the barrel, and if any part of the explosive chain could be felt, depending on the relative mass of the barrel it would perhaps be the movement of the projectile's mass within the barrel affecting the equilibrium or balance of the barrel, but not causing or contributing to any kind of recoil force, least not until the projectile escapes from the cylinder. So it is the internal gas pressure at the moment it escapes and expands from the barrel rather than the mass of the projectile that equates to the force of the recoil. The weight (i.e. mass times gravity) of the projectile is but a small portion of the total recoil force. <span style="text-decoration: underline">Theoretically, if a barrel was long enough to compensate for the full volume of the gas pressure, the forward motion of the projectile would literally stop and there would be no recoil.</span></div></div>

If recoil began at the instant a bullet moves, and thus building from that point throughout the bullet's barrel time, then the mantra of barrel harmonics and OCW that many of us worship as gospel would be a mute point. Recoil then would negate anything worthwile regarding muzzle ocillation and the "nodes" would be indistinguishable on paper. 'Course, there's a lot of folks that can't figure out OCW and barrel harmonics either...... </div></div>

Back in 2003-04, some SH members did some experiments and then wrote about them that made OCW and harmonics more explainable to many here and showed why it was critical to have OCW. Search Dan Newberry, David Wilson, and Chris Long.
In the 1mS of barrel travel the bullet moves, they did see recoil begin at that point (Newton), but it was so minute and infintesimally small (practically unmeasurable) that it would never overcome the greater forces of ocillation and nodes (that this movement creates) that make OCW so important.
Not that anybody really gives a shit.
This is almost like arguing Spin Drift at 100 yards.
Another reason that REAL range time spent shooting and having a well experienced shooter (like our little gnome Frank (JK on the gnome Frank)SHOW you things is way more beneficial than internet board arguments that get half scientific and 150% opinionated.
Frank or any other decent coach could show the OP the effects of free recoil versus more controlled "driving the rifle" in 10 minutes. Then the OP could choose which method gave him the best results.
 
Re: The effect of free recoil on POI

+1 jhuskey

What we all should appreciate is the need to control the rifle, that's to say, follow-through until recoil has subsided. My experiences suggest control/follow-through is what separates really brilliant shooters from others. Brilliant shooters recognize that any inconsistency in the position will have an effect on point of impact.

It appears to me that just a few thousandths of an inch in the relationship between the shooter, gun, and ground from shot to shot can have a dramatic effect on the perceived zero. I have some difficulty re-building my prone sling supported position consistently for every shot in 20 plus round strings of fire. If I get just a little lazy with re-building the position, overlooking any aspect of it, my 3/4 minute grouping ability opens up to about 2 MOA, as observed in reduced course 600 yard events (MR-31 target).

My point is, if there is any secret to good shooting, consistent control, for whatever forces are at work while the bullet is in or clearing the bore, is very, very important for the best results.

Some folks don't consider this stuff in their journey to shooting excellence; thus, they don't reach their destination.

BTW, my mentor, All Guard Shooter, CW4 Charles Green, has a very distinctive snap-in. I emulated it when I first got into HP, and still practice it today. Occasionally, I've observed folks who snap-in like this and wonder who it was originally for all of us that inspired such technique. It makes a real statement about holding hard.
 
Re: The effect of free recoil on POI

All,

About this thread in general: observation is where science starts; but, here, the observation regarding the muzzle movement, beginning after the bullet has left the bore, has been used to infer that since this movement is taking place after the bullet has left the bore, it has no effect on accuracy. This inference is reasonable; but, it is not a complete summation of what goes on when executing the firing task. As was alluded to by jhuskey, lowlight, and others, while the bullet is traveling through the bore many forces are at work, with inertia eventually giving way for the rifle to begin to move. For the best accuracy, these forces must be controlled while the bullet is still in the bore using suitable bone/artificial support.
 
Re: The effect of free recoil on POI

Sterling has such a great way with words describing in more technical terms of what is happening between the time the primer ignites and the bullet leaves the barrel.

Everything I posted about what I've learned is only proven to me and a few others that shoot the types of guns we do. I do believe it's more pronounced in our handguns at extreme distances and is way more critical to achieving the types of accuracy we do at those distances.

I'm not a sniper, swat or tactical shooter but do shoot handguns at what I think are pretty far distances. This sight is one of the few that I find very knowledgable and well informed shooters with real life experience to back up what they say.

In our quest for long range shooting we've found we can pretty consistantly hit a full size IPSC target at 500 yards with a Freedom Arms 44 magnum revolver with a 2.5-8 pistol scope. That may be an extreme but a single action revolver is one of the least forgiving types of guns to shoot accurately based on grip tension affecting POI. We also regularly hit some mighty small targets out to 1000 yards with a short barreled XP100 pistol at long range steel plate matches with the rifle guys which is more along the lines of velocity of the rifles and what affects POI. We're well past the point of jerking the trigger or giving it a good crunch and have spent a lot of time tweaking what works and what don't.

I don't have scientific proof to show but I can tell you after a lot of years shooting these guns at long distances at little targets that grip tension, wrist and finger placement, arm and shoulder pressure does indeed play a very important part in our accuracy quest. I do think that these same factors that we find very critical to us are just as important to a rifle shooter since they have their own obstacles that need to be recognized and made as identical from shot to shot as possible. It may not be quite as pronounced or critical but I think it's still there to a degree and affects POI could cause a miss.

This is directed more towards Outerspace, I'm not sure how far or how much you have shot at far targets but what separates the great shooter from the mediocre shooter at extreme distances is the one that pays attention to the smallest detail while preparing for each shot. Close up it's not as important but stretch it out and those lil things add up to a miss.

Been interesting reading this, I know that what I shoot does not really pertain to this sight but I have learned a lot from others that have posted here. Lots of knowledge on here and sometimes even though things can't be "proven in black and white I've learned to pay attention and adapt things from the long range rifle guys and adapt as needed to my shooting.

Topstrap
 
Re: The effect of free recoil on POI

What we're doing here is striving for a consistant launch of the bullet....not a consistant reaction to recoil.

The launch, as eluded to by your own sig line, dictates the point of impact. You consistantly control that via exactly what you say controls it...bone/artificial support; along with hold, tension, breathing, mental control, etc.

Where you begin to mislead yourself though, is believing that everything that transpires during the nanosecond or two that the bullet is in the bore is somehow affected by what happens a nanosecond or two after it leaves the crown as a matter of the physics of recoil....by then the bullet has left the bore and at the mercy of the elemements. IOW, too late for anything you as a mere human being can possibly do to influence it.

Where recoil comes into this, and makes a measurable difference....is the human fear of getting smacked with G forces and high decibles as a result of an explosion taking place in our face. He who shoots the best is the best at resisting the natural reaction to flinch away from the physical and audio "pain".

Holler all that follow through stuff that you want, and you are correct that it helps, but it's only an extension of your pre-shot disipline and can have absolutely nothing at all to do with the flight of the bullet AFTER it leaves the barrel, regarding the physics that is taking place. You cannot impart influence on a bullet after it's launched....I don't care how sterling a shooter you believe yourself to be.

If you want to explain free recoil vs. controlled recoil having different POI it's simply due to a different hold on the rifle, and thus a different attitude of bullet launch.

Nothing more, nothing less.......
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">I strongly disagree, first sentence. </div></div>

Really, that's odd, considering your own sig line; and the disipline you, I, and everyone else, preach about consistant hold, etc.

Care to expound a little further?

Since recoil forces that have the greatest affect on the combined mass of the shooter/rifle begin after the bullet leaves the bore thus inconsequential to bullet flight, it's only logical that the greatest concern, the part we actually have complete control over, is infact the launch.

Any variation of the muzzle direction from the time the primer pops to the bullet exit, whether that variation is derived voluntarily or involuntarily, results is a larger deviation from intended POA/POI.

It's simple cause & effect physics and logic....nothing more, nothing less.
 
Re: The effect of free recoil on POI

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">I strongly disagree, first sentence. </div></div>

Really, that's odd, considering your own sig line; and the disipline you, I, and everyone else, preach about consistant hold, etc.

Care to expound a little further?

Since recoil forces that have the greatest affect on the combined mass of the shooter/rifle begin after the bullet leaves the bore thus inconsequential to bullet flight, it's only logical that the greatest concern, the part we actually have complete control over, is infact the launch.

Any variation of the muzzle direction from the time the primer pops to the bullet exit, whether that variation is derived voluntarily or involuntarily, results is a larger deviation from intended POA/POI.

It's simple cause & effect physics and logic....nothing more, nothing less. </div></div>

The adjustment of the sight is, in part, a reaction to recoil, since the adjustment takes place after analysis of the effect.

Now, re read my last two posts. I think you may have been thrown off by my use of the word "reasonable" regarding a poster alluding to an observation of recoil apparently beginning after the bullet had left the bore. My thought on the matter is that the poster's observation had an inference which reached the wrong conclusion, since it did not consider observation of internal ballistics.

I think your views are similar to mine on the matter. At any rate, I have had the best results when I have built my position to control the rifle with consistency from trigger pull until recoil has subsided, for whatever the source/effect of involuntary rifle movement.
 
Re: The effect of free recoil on POI

Lets see if I can guess at some math, the bullet is 168/7000 pound, rifle is 12 pounds so the bullet is 2/1000 the weight of the rifle. Bullet starts at 0 and leaves the barrel at 2600fps so the average is about 1300fps for 2 ft, .0015384 second. The rifle travels at 2.6 fps or .0039998 feet or .05 inches if you load the bipod and get the mass equivalent of the rifle up to 60 lbs than the rearward travel would be down to .01 inches. As far as seeing movement in photography the shock wave of the chamber explosion is supposed to travel to the muzzle and back more than once before the bullet leaves the barrel, with all of that movement it would be difficult to see if the rifle was also moving back or not.
 
Re: The effect of free recoil on POI

That recent History Channel show on top sniper shots has a number of clips showing the bullet leaving the muzzle, the gun starts to move after the bullet has left on each one. Check it out and judge for yourself.
 
Re: The effect of free recoil on POI

I don't think the inference you made from your observation is thorough. But, I think you'd agree, to hit where aimed, it's important to maintain a steady position until the bullet clears the bore. Now, since NPA adjustment effects where the barrel will be pointed as the bullet clears the bore, if not recoil, what label do you give to the force which moves the rifle from a muscled point of aim to natural point of aim, assuming the shooter is consciously following through (not relaxing) until recoil has subsided. Obviously, this force is moving the rifle before the bullet has cleared the bore since it will effect shot placement. Finally, if your inference was fact, then inconsistent yet steady control of the rifle would produce results similar to those produced from consistent control, which does not happen. The fact is, consistent control from shot to shot is paramount to the best results. This is something you too can observe simply by changing the placement of the non-firing elbow while shooting from a prone unsupported position. Even a minuscule amount of inconsistency will cause POA/POI displacement. Remember, observations should include what's going on regarding the shooters relationship to the gun and ground, as well as the results at the target, in addition to the apparent non-movement of the rifle which you have observed.