Recoil effects on Accuracy

[mark-hunter]

Not necessarily.
I think, as per this example, maybe not all the people read manual before use.

 

[Forrest Halley]

I love it! Three exrimfire shooters talking about zeros and recoil. Can we expand this discussion into the possible degradation of accuracy due to the necessary shift from bladed to square stance? How about over gripping the rifle? Anticipated recoil is a big downplay on accuracy. I believe shooters only anticipate recoil they are going to have difficulty handling be it from the known violence of the event or building discomfort/existing soreness. I could care less about my .223 or 12 gauge round's recoil, but give me that Lott and I begin to pay closer attention to presentation and position of hands and cheek. After a few rounds, I begin to anticipate the recoil and it's time to play with something else.

 

[mark-hunter]

Well, some rimfire shooters, also use muzzle brake....

 

[Ray B]

the math is simple enough.

When I was in the 6th grade we watched a film about mirrors and how they worked. At one point it showed a person in a car looking out the window into the dark. What showed was the reflection of the person. the narrator then said "why the persons image is reflected is obvious". Years later I was discussing a problem with the head of the math department at college. He said usually when the answer to a problem is obscured and the person lacks understanding, they will say something such as "the answer is obvious". Appears such people attended LSU.

 

[One Day...]

We are likely talking past one another (it has happened before ), and it is also possible we are conflating the effects of position and hold with open sight picture and telescopic sights. I too am an old competitive smallbore shooter (Louisiana State Collegiate champion in '73!! - that is laughing at myself @bruce moulds not bragging) and I agree that everything alters to some extent in every position - all of which affects sight picture. My field and range experience with both military and personal firearms has been the same. In fact, all of my final sight-in shots with open sights are always done from a field rest (nowadays usually sticks). But scopes reticles are on a single plane, and in my experience at least, far less subject to the effect of position on sight picture. So, any difference between the rest (lead sled, sand bag, etc) and the field sight picture is not really much of an issue. I personally believe that is the actually greatest contributor to my observations of no detectable difference between the lead sled POI and the field.

I agree that "muzzle flip" can affect accuracy, but I don't think it is meaningful. We would both agree, that without a shooter and no hindrance (shoulder or lead sled) a rifle will recoil straight back with equal and opposite force as that generated by the firing of the projectile. Initial mitigation is rifle weight and bore friction (back to that in a bit). I was always taught that the initial recoil impulse (which does indeed begin at ignition) is relatively small until the bullet clears the barrel when the gas jet accentuates the perceived impact - essentially why muzzle brakes work. I am a history major, not a physicist, but let's say the typical rifle bullet leaves the muzzle in about 1 millisecond (I am deliberately doing easy math by the way - I tried to take my required college math classes with the basketball team ) and let's say a rifle moves 300 inches in one second, then it can only move .3 inches during the period of time the bullet is in the barrel regardless of how the firearm is held. So worst case, the rifle's point of aim is only influenced by whatever muzzle flip occurs in the first third of an inch of movement under recoil. I admit that .3 inches over extended ranges can be meaningful, but it also means we're actually compensating for only a small initial part of the recoil impulse.

Thus again, I think the real purpose of the vast majority of our technique is to mitigate against the perceived and anticipated movement of all stuff coming out the end of the barrel - not to mitigate the effect of actual muzzle flip. None of which has very much to do with multiplane sight picture other than make technique all the more demanding.

With respect to friction. I am not even sure a meaningful measurement could be made for a rifle. But it is a real input of the internal ballistics of say a 155mm artillery round. The opturating bands create friction in the bore, mitigating recoil and "flip" to some small extent which nevertheless is perceivable when engaging a target at 18 kilometers rather than 180.

Interesting discussion... (I do not mean this as a facetious remark)

Sight picture...
I had never been exposed to the concept that positions alter sight pictures. I personally always shot with, obviously, the rear micrometer (can't remember the diameter of the aperture) and a globe front sight, and, of course, the rifle needed to be reconfigured (stock length, height of comb, angle of rear plate, etc.) for each position in order to achieve a proper sight picture, but I had never heard that once achieved, that sight picture was actually different from position to position. I am not challenging the point, Joe, I had just never heard of it in either civilian competition circles (I too won a number of regional competitions in France - they do not have States - and was coached), nor military competition circles (I went through sniper training in the French Army, and later competed both pistol and rifle in the reserve, where again I was coached). Nor did I ever notice by myself for that matter, that my sight picture (whether iron or glass) changes from one position to the next.

But maybe it is an indirect effect of having been drilled so much about acquiring the proper sight picture that I do not realize this. I can certainly agree wholeheartedly that changing position changes how I achieve the sight picture, but I do not know that it changes the sight picture itself, once achieved.

Jet effect...
I agree regarding the jet effect contributing to recoil. But, how much of the recoil is produced by the initial impulse and how much by the jet effect, I know not. It all happens too fast for me. Going by fuzzy memory, the regulation 7.5x54 load in a MAS 49/56 (say .308 in a M14 for American purposes) took 0.0007 second to exit the barrel. One thousandth of a second is 0.001, so we are talking about 7 tenth of a millisecond. The French sniper training (and rifle tuning) did address the jet effect, but as a component of BOTH bullet path and recoil control. The influence of the gas jet on external ballistics comes from the fact that because the gas jet comes out of the barrel faster than the bullet, the gas jet has a significant influence on the bullet path, and it can steer the bullet upward, downward or sideways depending on how it is applied. To folks with French military sniper training, the proof of what I say is embedded in the fact that snipers where prohibited to remove or move the flash hider of the FRF1 rifle, as it influenced the axis of the gas jet.

For the AH readers, I will use a different validation that will resonate. Deviating the gas jet in order to steer the bullet in a specific direction was the reason why Sabatti infamously used the Dremel to butcher the crown of their double rifles to compensate for the poor mechanical convergence work on their double barrels.

To conclude on this point, the control of the recoil includes the control of the gas jet axis, which affects the flight of the bullet.

Barrel friction...
I of course totally agree that this factor is at play, even in a rifle barrel. This is the reason why the same load flies faster or slower from different individual barrels, and the same load may show pressure signs in some barrels and no such signs in other barrels. How does this factor play into the recoil dynamics, I know not in detail, beside the fact that it obviously affects muzzle velocity, which in turns affects recoil.

In summary...
So, in summary, I have no specific knowledge of how sight picture and recoil and/or recoil control interact, and how barrel friction and recoil control interact, so I am not able to comment on those, but I do believe that it is a fact that controlling the axis of the gas jet is an integral part of recoil control.

What determines where the bullet is going is 1) where the barrel points when the bullet leaves, and it does not take much barrel movement at all to impart several MOA of divergence to the trajectory, and the fact is that such minute movements of the barrel do happen while the bullet is still in the barrel. This is compounded by 2) how the gas jet pushes and/or steers the bullet as it leaves the barrel and for a short distance after it leaves it.

To make it all simple, the shooters who can control the recoil just as well and as consistently as a led sled does will not see a discernible shift of point of impact, with or without the sled, but such shooters are very rare and very far in between, and none of any of the above challenges the fact that a lead sled certainly allows shooters to handle hard recoil rifles better at the bench

 

[Red Leg]

When I was in the 6th grade we watched a film about mirrors and how they worked. At one point it showed a person in a car looking out the window into the dark. What showed was the reflection of the person. the narrator then said "why the persons image is reflected is obvious". Years later I was discussing a problem with the head of the math department at college. He said usually when the answer to a problem is obscured and the person lacks understanding, they will say something such as "the answer is obvious". Appears such people attended LSU.

Why Ray, are you trying to be deliberately insulting? You can surely do better than that. What’s worse, and regrettably, I didn’t actually go to LSU. You just missed on that one. I simply pull for them as a die hard fan and native South Louisianan. My post MA fellowship was at Georgetown University - the Walsh School of International Affairs. None of which, of course, has anything to do with math or physics. I merely pointed out a basic bit of math concerning recoil that is well known to many, and which simply speaks to the very limited time a bullet might actually be affected by recoil and subsequent barrel movement during the overall recoil event.

If, on the other hand, you still have questions about the lead sled, please ask them. I am happy to provide any additional observations you might find useful based upon my actual extensive use of the product.

 

[Red Leg]

Interesting discussion... (I do not mean this as a facetious remark)

Sight picture...
I had never been exposed to the concept that positions alter sight pictures. I personally always shot with, obviously, the rear micrometer (can't remember the diameter of the aperture) and a globe front sight, and, of course, the rifle needed to be reconfigured (stock length, height of comb, angle of rear plate, etc.) for each position in order to achieve a proper sight picture, but I had never heard that once achieved, that sight picture was actually different from position to position. I am not challenging the point, Joe, I had just never heard of it in either civilian competition circles (I too won a number of regional competitions in France - they do not have States - and was coached), nor military competition circles (I went through sniper training in the French Army, and later competed both pistol and rifle in the reserve, where again I was coached). Nor did I ever notice by myself for that matter, that my sight picture (whether iron or glass) changes from one position to the next.

But maybe it is an indirect effect of having been drilled so much about acquiring the proper sight picture that I do not realize this. I can certainly agree wholeheartedly that changing position changes how I achieve the sight picture, but I do not know that it changes the sight picture itself, once achieved.

Jet effect...
I agree regarding the jet effect contributing to recoil. But, how much of the recoil is produced by the initial impulse and how much by the jet effect, I know not. It all happens too fast for me. Going by fuzzy memory, the regulation 7.5x54 load in a MAS 49/56 (say .308 in a M14 for American purposes) took 0.0007 second to exit the barrel. One thousandth of a second is 0.001, so we are talking about 7 tenth of a millisecond. The French sniper training (and rifle tuning) did address the jet effect, but as a component of BOTH bullet path and recoil control. The influence of the gas jet on external ballistics comes from the fact that because the gas jet comes out of the barrel faster than the bullet, the gas jet has a significance influence on the bullet path, and it can steer the bullet upward, downward or sideways depending on how it is applied. To folks with French military sniper training, the proof of what I say is embedded in the fact that snipers where prohibited to remove or move the flash hider of the FRF1 rifle, as it influenced the axis of the jet gas.

For the AH readers, I will use a different validation that will resonate. Deviating the gas jet in order to steer the bullet in a specific direction was the reason why Sabatti infamously used the Dremel to butcher the crown of their double rifles to compensate for the poor mechanical convergence work on their double barrels.

To conclude on this point, the control of the recoil includes the control of the gas jet axis, which affects the flight of the bullet.


Barrel friction...
I of course totally agree that this factor is at play, even in a rifle barrel. This is the reason why the same load flies faster or slower from different individual barrels, and the same load may show pressure signs in some barrels and no such signs in other barrels. How does this factor play into the recoil dynamics, I know not in detail beside the fact that it obviously affects muzzle velocity, which in turns affects recoil.

In summary...
So, in summary, I have no specific knowledge of how sight picture and recoil and/or recoil control interact, and how barrel friction and recoil control interact, so I am not able to comment on those, but I do believe that it is a fact that controlling the axis of the gas jet is an integral part of recoil control.

What determines where the bullet is going is 1) where the barrel points when the bullet leaves, and it does not take much barrel movement at all to impart several MOA of divergence to the trajectory, and the fact is that such minute movements of the barrel do happen while the bullet is still in the barrel; and 2) how the gas jet pushes and/or steers the bullet as it leaves the barrel and for a short distance after it leaves it.

To make it all simple, the shooters who can control the recoil just as well and as consistently as a led sled does will not see a discernible shift of point of impact, with or without the sled, but such shooters are very rare and very far in between, and none of any of the above challenges the fact that a lead sled certainly allows shooters to handle hard recoil rifles better

As I surmised, I am pretty sure you and I are actually saying very much the same thing. The recoil event has a very real effect on bullet impact. Where we may differ is by how much the path of the bullet is affected by the event itself and how much by the shooter’s reaction to it. And there too we may also be saying essentially the same thing. I would simply argue that the lead sled allows the shooter to overcome a large set of those externals to achieve a properly sighted in rifle. Subsequent shooting ofF rests or from field positions does indeed necessitate duplicating that control as much as possible.

 

[375 Ruger Fan]

When I was in the 6th grade we watched a film about mirrors and how they worked. At one point it showed a person in a car looking out the window into the dark. What showed was the reflection of the person. the narrator then said "why the persons image is reflected is obvious". Years later I was discussing a problem with the head of the math department at college. He said usually when the answer to a problem is obscured and the person lacks understanding, they will say something such as "the answer is obvious". Appears such people attended LSU.

@Ray B : Talking smack about people that attended LSU???? How did you connect the dots on this? I did attend LSU grad school, but I will take your comment in stride.

BTW, congratulations on making it to 6th grade and watching films.

Super slow motion video clearly shows the bullet leaves the barrel before recoil occurs. Watch the video, just like watching films in 6th grade and the answer will become obvious to you.

 

[Fastrig]

I love it! Three exrimfire shooters talking about zeros and recoil. Can we expand this discussion into the possible degradation of accuracy due to the necessary shift from bladed to square stance? How about over gripping the rifle? Anticipated recoil is a big downplay on accuracy. I believe shooters only anticipate recoil they are going to have difficulty handling be it from the known violence of the event or building discomfort/existing soreness. I could care less about my .223 or 12 gauge round's recoil, but give me that Lott and I begin to pay closer attention to presentation and position of hands and cheek. After a few rounds, I begin to anticipate the recoil and it's time to play with something else.

Tend to agree with you on anticipated recoil. If you want your accuracy to go to hell in a hand basket, start shooting a caliber you aren’t comfortable shooting or sore from shooting. Natural instinct causes you to tense and do all kinds of little things you wouldn’t normally do with calibers you are comfortable with. You can train that out of yourself in some instances, with enough time and practice, but if you genuinely retain that “I know its coming” little flinch in the back of your mind you are never going to be as good with that caliber as you are with the ones where that mind flinch is absent.

 

[Ray B]

That's a real knee-slapper Mr. Ruger 375 fan. And Mythbusters!! Now there's some credible evidence. I must say you've convinced me.

 

[One Day...]

@Ray B Super slow motion video clearly shows the bullet leaves the barrel before recoil occurs. Watch the video, just like watching films in 6th grade and the answer will become obvious to you.

Great video indeed that actually shows that the barrel and slide are already in full rearward motion before the bullet leaves the barrel.

TO SEE IT, put your mouse cursor at 0:10; focus your attention at the gas escaping upward from the ejection port, or at either end of the frame where you see the slide move over the frame; and click the mouse repeatedly as the video reaches 0:11 to repeat a couple times the frames between 0:10 and 0:11 and you will clearly see that the barrel & slide rear movement starts well before the bullet leaves the barrel, which has been my point all along.

Truth be told, this is not an earth shattering point to make because Newton's third law - for every action, there is an equal and opposite reaction - is hardly debatable, but the video clearly shows it in action.

Now, keep in mind that a 1911 barrel is typically 5" long and that a big bore rifle barrel is typically 22" to 25" long. The rifle bullet has 4.5 to 5 times as much distance to travel while the barrel is already in recoil motion. Granted, the rifle bullet reaches at least twice the muzzle velocity of the pistol (2,100+ fps vs. 800 to 1,000 fps depending on load), but the rifle bullets too starts from a stand still - just as the pistol bullet does - and takes time to accelerate. As a result, the rifle bullet stays in the barrel roughly about twice as long as the pistol bullet does, and the forces involved to accelerate the rifle bullet are much higher (larger powder charge) therefore the acceleration in both direction is much larger.

It is therefore easy to see why the name of the game is recoil control, i.e. maintaining the rifle barrel pointing at exactly the same point during the time it recoils with the bullet still traveling through it, in order to achieve consistent accuracy.

If it was not, it would be as easy to shoot accurately a .378 Wby as it is to shoot a .223, and we all know that it is not...

Great video, Thank You for posting it

 

[Red Leg]

Great video indeed that actually shows that the barrel and slide are already in full rearward motion before the bullet leaves the barrel.

TO SEE IT, put your mouse cursor at 0:10; focus your attention at the gas escaping upward from the ejection port, or at either end of the frame where you see the slide movement over the frame; and click the mouse repeatedly as the video reaches 0:11 to repeat a couple times the frames between 0:10 and 0:11 and you will clearly see that the slide rear movement starts well before the bullet leaves the barrel, which has been my point all along.

Truth be told, this is not an earth shattering point to make because Newton's third law - for every action, there is an equal and opposite reaction - is hardly debatable, but the video clearly shows it in action.

Now, keep in mind that a 1911 barrel is typically 5" long and that a big bore rifle barrel is typically 22" to 25" long. The rifle bullet has 4.5 to 5 times as much distance to travel while the barrel is already in motion. Granted, the rifle bullet reaches at least twice the muzzle velocity of the pistol (2,100+ fps vs. 800 to 1,000 fps depending on load), but the rifle bullets too starts from a stand still - just as the pistol bullet does - so the rifle bullet stays in the barrel roughly about twice as long as the pistol bullet does, and the forces involved to accelerate the rifle bullet are much higher (larger powder charge) therefore the acceleration in both direction is much larger.

It is therefore easy to get why the name of the game is recoil control, i.e. maintaining the rifle barrel pointing at exactly the same point during the time it recoils with the bullet still traveling through it, in order to achieve consistent accuracy.

Great video, Thank You for posting it

Hmmm. And here I was thinking it made my point perfectly. The super slo-mo demonstrates quite clearly that the effect of recoil is almost immaterial until after the bullet has left the barrel. The initiation of the process does cause some tilt (or initial slide movement in this case), but as I noted above, that initial movement can not have much real impact on trajectory. This doesn't mean that recoil doesn't affect the shooter - it absolutely does. And we need to expend every minute we can overcoming our reaction to it - particularly our reaction to the anticipation of it - as much as we can. But effect on the bullet itself and its trajectory? Not so much.

Great video, thank you for posting it

Regardless of how we view the video or the math, good shooters do exactly the same things to mitigate the effect on the shooter of recoil.

 

[One Day...]

Well, if "the effect of recoil is almost immaterial until after the bullet has left the barrel" on high power rifles, then everyone who has ever fired a rifle should shoot groups as tight with a .300 RUM, .338 Win, .375, .416, .458, etc. as they do with a .22 LR, right?, because "that initial movement can not have much real impact on trajectory," right? and "effect on the bullet itself and its trajectory? Not so much," right?

Yet, most shooters do not shoot as well a .338 (without a muzzle break) as they do a .223. Why would that be?

Ah yes, they flinch. Well, some do, but many do not, and if the issue was recoil pain, subsequent anticipated recoil and induced flinch (these are very real issues, do not read me wrong here), then they should all be addressed quite effectively when shooters put on a Past® Magnum Recoil Shield or equivalent. Yet, curiously, people who shoot with these do not hurt themselves anymore - which is great, and do not flinch anymore, but bizarrely their groups do not automatically shrink to 1" at 100 yards. Why is that?

And apparently enough shooters struggle sufficiently to produce a sighting group with a high power rifle, for an entire lead sled etc. industry to have emerged to offer products designed to neutralize the effect of recoil on people sighting their rifle - including people who do not flinch and who are not afraid of their rifle - so that they can produce groups tight enough to actually sight their rifle. Why is that?

Etc. etc. etc.

All I will say is that the literature has been replete for over 100 years of people believing that hard recoiling rifles are harder to shoot accurately than mild recoiling rifles, and not all these authors - by far - were flinching. Conversely, I had never heard someone make a serious argument that recoil does not affect accuracy. This one is new on me. Never too old to learn...

As usual, to each their own, all that matters is that people believe in their rifle, their zero, and themselves enough to shoot acceptably in the field the 2 to 3 MOA shots that are sufficient to kill most animals with a 6" vital area out to 200 yards

 

[Ray B]

All of this gets to the point that in a closed system movement of matter will result in a shift of the balance point. Prior to the bullet leaving the bore the change in balance point will result from the bullet changing position from one end of the barrel to the other plus the powder, now turned to gas will have changed position from the case to spread-out from the case to the bullet base. The distance that the balance point moves will be the initial recoil and it will occur in the time the bullet moves the distance of the barrel.

 

[375 Ruger Fan]

Another super slow video (1,000,000 frames per sec)................ever so slight rearward movement can be detected on the gun. Emphasis on slight. The majority of recoil happens after the bullet leaves the barrel.

This video is 45,000 frames per sec. Looks like the bullet is out of the barrel before significant recoil occurs.

 

[Red Leg]

Actually, there is quite a bit of research showing that the total recoil event does not affect the trajectory of the bullet a great deal. It does, however, have a very real affect on the shooter; the larger the bore the greater the effect. I have experienced, and seen it very often in new shooters, where a first shot is perfect and subsequent shots are all over the place. That has nothing to do with the bullet lingering in the bore and everything to do with a breakdown of shooting technique after the first recoil event. The bullet went a different place because the bore was pointed a different place at the time the rifle was fired. That has everything to do with shooting technique of which a flinch is merely one potential input. It is why repeatability of technique is so important - so the bore is pointed in the same way at the target every time the trigger is released - not to hold it on the same location as the bullet meanders its way down the barrel, but so it is pointed at where the bullet needs to go. It is why shooters have a harder and harder time as the caliber goes up. Their technique breaks down. Remember, it is impossible for a muzzle break to work if the vast amount of the recoil event, the gas jet, didn’t happen until after the bullet was long gone.

The two videos above, particularly the second which is a rifle, are pretty dramatic illustrations of the effect of the gas jet.

Where we are talking past each other is the effect of shooting technique. We would advocate the same things - breathing control, correct trigger pull, cheek weld, etc, etc,. But we are not mitigating the effect of recoil on the bullet’s trajectory very much. We are mitigating totally our effect on where the bore is pointing at the instant of primer ignition.

 

[Forrest Halley]

Please don't compare a handgun to a rifle. Changing balance point during recoil is just bizarre. We've gone through gas jet angles and time in bore and even LSU. Geaux Tiggers! Recoil affects accuracy; with an "A"! I don't care when it happens or what techniques break down. You all know it happens and despite our varying theories it affects us. Except for those of us who are truly terrible marksmen and shoot the same shoddy groups with all their rifles from .22 to .458.

 

[375 Ruger Fan]

Please don't compare a handgun to a rifle. Changing balance point during recoil is just bizarre. We've gone through gas jet angles and time in bore and even LSU. Geaux Tiggers! Recoil affects accuracy; with an "A"! I don't care when it happens or what techniques break down. You all know it happens and despite our varying theories it affects us. Except for those of us who are truly terrible marksmen and shoot the same shoddy groups with all their rifles from .22 to .458.

Tigers, one "g".

I am right there with you on your last sentence, as I am usually a mediocre shot regardless of caliber.

 

[Red Leg]

Tigers, one "g".

I am right there with you on your last sentence, as I am usually a mediocre shot regardless of caliber.

And there I was assuming he was a Cajun fan of A.A. Milne.

 

[Longwalker]

I don't know very much about the technical effects of recoil on rifles, but this discussion does make me curious. If recoil had no effect on the point of impact of a bullet, I would conclude that the standard theory about double rifles only regulating with one specific load would be invalid. Since I have observed the effects of changing the powder charge / bullet weight / recoil / velocity when shooting a double rifle, I have to conclude that recoil during the time a bullet is in the rifles barrel actually matters quite a lot. If it were not so all SxS double rifles would shoot multiple loads to the same general point of convergence. Since we know this is not true, recoil moving the rifle while the bullet is still in the barrel must be the explanation why.