Range Report Change in poi?

Re: Change in poi?

How does what you have your rifle propped on change your POI? I can't see how it would physically "change" anything about your rifle. How you shoot the rifle maybe, but not the rifle.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pepperbelly</div><div class="ubbcode-body"> Is it normal to have defferent points of impact when shooting from sandbags and then going to a bipod?

Jim </div></div>

Perhaps, POA is different?
 
Re: Change in poi?

When the gun is sitting on bags and is fired, the gun recoils back longitudinally as the bullet gains momentum in the barrel.

When the gun is supported on a bi-pod, the bipod can move the front end of the gun vertically while the rest of the gun is recoiling from the same effets as above. It has been said that if you take aim on a bi-pod, then pull the gun back into your sholder, you mitigate this rise {by changing the geometry of the legs versus gun barrel which is the cause of the rise}.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DesertHK</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pepperbelly</div><div class="ubbcode-body"> Is it normal to have defferent points of impact when shooting from sandbags and then going to a bipod?

Jim </div></div>

Perhaps, POA is different?</div></div>




........bingo.......
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pepperbelly</div><div class="ubbcode-body"> Is it normal to have defferent points of impact when shooting from sandbags and then going to a bipod?

Jim</div></div>

It's not a concept so much about being normal, as much as it's about being consistent, or not consistent. With consistent, you can expect what may be normal, shots going on call.

Control of the rifle from a consistent position/support, from trigger pull until the bullet clears the bore, or recoil subsides, will usually provide a predictable recoil pattern, Changing the position and/or support will change the pattern of recoil, and, thus, the rifle will need to be re-zeroed for such a change.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">
Control of the rifle from a consistent position/support, from trigger pull until the bullet clears the bore, or recoil subsides, will usually provide a predictable recoil pattern, Changing the position and/or support will change the pattern of recoil, and, thus, the rifle will need to be re-zeroed for such a change. </div></div>


I cant say I agree with this statement, though I'm no expert. Zero is zero, the shooter regardless of position should be able to score a "hit", also some one else shooting the same rifle should be able to score a hit.

I understand what your saying, but acording to your statement you should have prone zero, a kneeling zero, a standing zero and so on... for me, zero is zero and if I hit bulls prone but shoot high and right kneeling then I need to adjust the way I am shooting not the rifle.

just my 2 cents
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MrMike</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">
Control of the rifle from a consistent position/support, from trigger pull until the bullet clears the bore, or recoil subsides, will usually provide a predictable recoil pattern, Changing the position and/or support will change the pattern of recoil, and, thus, the rifle will need to be re-zeroed for such a change. </div></div>


I cant say I agree with this statement, though I'm no expert. Zero is zero, the shooter regardless of position should be able to score a "hit", also some one else shooting the same rifle should be able to score a hit.

I understand what your saying, but acording to your statement you should have prone zero, a kneeling zero, a standing zero and so on... for me, zero is zero and if I hit bulls prone but shoot high and right kneeling then I need to adjust the way I am shooting not the rifle.

just my 2 cents </div></div>

Mike why do you think they make us wrap our support hand on the sling of our M16's when we shoot for basic until it's numb and tell us not move it? I dont think it's because they want to torture us. The pressure applied on the rifle for each position is different this difference in pressure how miniscule it maybe will affect the bullet's travel inside the barrel (although this might not apply to competition shooters since they have mastered a way on how to apply consistent pressure on different positions). The next time you shoot try to hold the rifle as hard as you can and as loose as you can then compare the groups. Also while shooting with a bipod try to shoot with the bipod preloaded vs the bipod not preloaded. I bet you there's going to be a difference.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MrMike</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">
Control of the rifle from a consistent position/support, from trigger pull until the bullet clears the bore, or recoil subsides, will usually provide a predictable recoil pattern, Changing the position and/or support will change the pattern of recoil, and, thus, the rifle will need to be re-zeroed for such a change. </div></div>


I cant say I agree with this statement, though I'm no expert. Zero is zero, the shooter regardless of position should be able to score a "hit", also some one else shooting the same rifle should be able to score a hit.

I understand what your saying, but acording to your statement you should have prone zero, a kneeling zero, a standing zero and so on... for me, zero is zero and if I hit bulls prone but shoot high and right kneeling then I need to adjust the way I am shooting not the rifle.

just my 2 cents</div></div>

You may have an opportunity to learn something here. Indeed, my zero's are different, not only for distance, but for position as well. For example, my standing zero is about a minute lower than one used for prone; and, my windage is about a 1/2 minute left of what I'd put on the gun for prone. Some of this has something to do with cant, although, most of it is about recoil.

Obviously, I'm shooting for score, and X's are important, so I'm always refining zero's to conditions that effect zero's.

In addition to position effecting zero's, wind, light and temperature will also cause need for adjustment to put em in the X ring.

I doubt that, unless you're a master class hi-power competitor shooting in competition, you'd have any need to refine zero's as caused by change in position, as the value for zero refinement may be moot. And, shooting E type targets without the aid of a data book would certainly preclude zero refinement; plus, shooting less than match grade ammunition would cause zeroing refinement to be just as elusive.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MrMike</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">
Control of the rifle from a consistent position/support, from trigger pull until the bullet clears the bore, or recoil subsides, will usually provide a predictable recoil pattern, Changing the position and/or support will change the pattern of recoil, and, thus, the rifle will need to be re-zeroed for such a change. </div></div>


I cant say I agree with this statement, though I'm no expert. Zero is zero, the shooter regardless of position should be able to score a "hit", also some one else shooting the same rifle should be able to score a hit.</div></div>

It is a well known phenomonom that giving one sniper another sniper's weapon will change the zero! That is, just the way one holds the gun and the way ones body reacts to the gun being fired effects the vibrations of the gun and the PoI.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MrMike</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">
Control of the rifle from a consistent position/support, from trigger pull until the bullet clears the bore, or recoil subsides, will usually provide a predictable recoil pattern, Changing the position and/or support will change the pattern of recoil, and, thus, the rifle will need to be re-zeroed for such a change. </div></div>


I cant say I agree with this statement, though I'm no expert. Zero is zero, the shooter regardless of position should be able to score a "hit", also some one else shooting the same rifle should be able to score a hit.</div></div>

It is a well known phenomonom that giving one sniper another sniper's weapon will change the zero! That is, just the way one holds the gun and the way ones body reacts to the gun being fired effects the vibrations of the gun and the PoI.</div></div>

It comes from a bad habits and it is 100% a shooter thing.

Funny thing is, as we started to refine things we find that, for example, Jacob who own Rifles Only is 6ft tall and has had two hip surgeries, I'm 5.2" with none of those other things and we have the exact same zero now. It wasn't always this way, but now we have the same zero because we drive the rifles in a similar fashion. But refining our body position and trigger that shift magically vanished.

As, well, my zero doesn't change from right handed to left handed shooting, its' the same. As well my positional shooting doesn't change. It definitely within a bullet width of its self.

Aside from trigger issues we see, the thing that changes the POI is the cheek weld, however if the rifle truly zeroed the Paralllax adjustment would eliminate any shift because of a cheek position.

Old norms are changing everyday. We're learning that if you truly zero the rifle you won't find the problems people have in the past. A zero should be a zero, what changes is improper input from the shooter. Its all us who affect these things, as left alone the rifles will do the same thing over and over. We cause the shifts... the better you drive the rifle, the less negative inputting will occur.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MrMike</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">
Control of the rifle from a consistent position/support, from trigger pull until the bullet clears the bore, or recoil subsides, will usually provide a predictable recoil pattern, Changing the position and/or support will change the pattern of recoil, and, thus, the rifle will need to be re-zeroed for such a change. </div></div>


I cant say I agree with this statement, though I'm no expert. Zero is zero, the shooter regardless of position should be able to score a "hit", also some one else shooting the same rifle should be able to score a hit.</div></div>

It is a well known phenomonom that giving one sniper another sniper's weapon will change the zero! That is, just the way one holds the gun and the way ones body reacts to the gun being fired effects the vibrations of the gun and the PoI.</div></div>

It comes from a bad habits and it is 100% a shooter thing.

Funny thing is, as we started to refine things we find that, for example, Jacob who own Rifles Only is 6ft tall and has had two hip surgeries, I'm 5.2" with none of those other things and we have the exact same zero now. It wasn't always this way, but now we have the same zero because we drive the rifles in a similar fashion. But refining our body position and trigger that shift magically vanished.

As, well, my zero doesn't change from right handed to left handed shooting, its' the same. As well my positional shooting doesn't change. It definitely within a bullet width of its self.

Aside from trigger issues we see, the thing that changes the POI is the cheek weld, however if the rifle truly zeroed the Paralllax adjustment would eliminate any shift because of a cheek position.

Old norms are changing everyday. We're learning that if you truly zero the rifle you won't find the problems people have in the past. A zero should be a zero, what changes is improper input from the shooter. Its all us who affect these things, as left alone the rifles will do the same thing over and over. We cause the shifts... the better you drive the rifle, the less negative inputting will occur. </div></div>


All,

I've got more zero's than Carter's got pills; and, it has nothing to do with having an inconsistent position, or other. I'm talking about zero's for prone, sitting and standing positions. It's mostly about recoil being peculiar to the particular position/platform. Zero's also change with temperature and light. The only thing for certain is that the bullet always goes in the direction the barrel is pointed. Understand where it's pointed and you've got it made. Just adjust the rifle's sights to hit where aiming at the given distance-that's your zero.

BTW, you've gotta be able to shoot groups before you start adjustin' sights. Some shooters have so many problems getting and maintaining a consistent position, as well as aquiring a consisent perspective of aim (both sight alignment and hold), it's doubtful they could ever get a good zero, without a lot of reps, no matter what manner the gun is shouldered.
 
Re: Change in poi?

Sterling, I think you are also talking about open sights which makes a big difference because you can't dial out the changes without dialing on a new zero.

In most of these situations guys are talking about with scopes and you bring it around to open sight shooting without qualifying that first.
 
Re: Change in poi?

Yes, bags versus bipod versus sling can have a 1+MOA (total combined windage and elevation shift). My palma rifle is on the order of a 3 MOA shift vertical and right with bags versus its zero with a sling and coat.

Zero ain't zero.
 
Re: Change in poi?

Hate to tell you, but with a tactical rifle, a zero, has to be a zero... lives depend on it being so.

Great that your palma rifle is different, but a 3 MOA shift would kill someone,period.

the game you play is completely different from the tactical shooting world, and while many skills will translate, many will not. To give you an example. We use the Sniper's Hide Dot Target weekly in our training. The last row is engaged by standing with your rifle in your hand starting with 20 seconds you have to drop and fire one round. It continues down so the last dot is engaged with 10 seconds the same way. There is no prep time, no putting your jacket on, checking your sling or shooting for score with an insanely generous time limit. Doesn't take away from the difficultly of what you do but it doesn't translate the same, nor should it.

Sling shooting in the tactical world is a last resort thing use to get over obstacles, it's not for score with specialized gear for the event. It's something required right the fuck now and barely practical in the real world. Most people would use a buddies shoulder before going to a sling.

A tactical rifle is designed to take a certain amount of abuse. Most rifles, even some purported tactical rifles cannot. I can tell you over the course of the last PR 1 & 2 we had only about 2 rifles out of 11 on the line that succeeded in maintaining their zero on a daily basis allowing the shooters to successfully engage the targets. That isn't what they are supposed to do, that is identifying a problem. If my rifle won't hold zero across the course, I'm getting rid of it... period. This is one of the primary reasons why an Accuracy International is what it is, to hold that zero under combat conditions. Do you think they have time to check shifts and re-zero, most FOBs don't even have ranges.

Constantly blurring the lines between tactical and highpower really doesn't serve any purpose in explaining something to a shooter with an issue. They are apples and oranges when you really boil it done. Highpower shooting is an excellent training tool, and I highly recommend if someone has the means or the time to explore and shoot it, but it's not the same. They have removed all the stresses that even the most basic training tools in tactical shooting. Does it mean I can roll into highpower and expect to do well, not at all, even if I invested in all the right gear, it still requires my training to focused in discipline. Same as I guarantee if I gave Leo and Charles two free slots to one of our matches, I would barely expect them to finish in the top 20 because its so different then what they are used too. Hell, the timings along with the run and guns would be completely out of their comfort zone, not to mention the large amount of support side shooting we do... I don't either practices very much shooting their competition rigs from the support side, although a tactical shooter should everytime they go out.

People shouldn't confuse shooting with iron sights with shooting with a scope, and if your POI is shifting when you go from position to position with your tactical rig, you have a problem.
 
Re: Change in poi?

I have a couple of Tactical Rifles and a bunch of Palma/Prone rifles. With a scope your zero is different going from a sling to a bi-pod. Before I got my tactical rifles up and running I let newbies shoot my Palma/Prone guns off a bi-pod. (Parker Hale will fit in the forend rail) Windage is off more than anything.

 
Re: Change in poi?

If your zero is different you have a problem with your stock... its being torqued. Or you not checking your NPA properly and you're just not shooting as good as you can with your bipod.

But the zero is the zero...

if the shooter is off, that is not the rifle, that is a training issue. I bet the windage is off to the right too.
 
Re: Change in poi?

The original question was about bags versus bipods. I'll extend that to mean bench with bags versus prone with bipod. Bag techniques vary as do bipod techniques, not to mention the variation between the two.

If you want a zero for shooting prone with a bipod with your prone bipod shooting technique employed, then I suggest you get that zero shooting prone with your bipod using your prone shooting technique.

The more recoil the WS has (combination of weight, brake/no brake, chambering, bullet weight) then the more POI shift it will have as you change positions and techniques. This is true regardless of what discipline you subscribe to.

As with my precision field rifle WSs I want a repeatable POI aka "zero" within a click of where I think it will be, I get said zero with how I intend to shoot the rifle the most - prone with a bipod. I'll also go with the most weight and least recoil the game can tolerate so that my POI shifts when changing positions (e.g, sitting with shooting sticks) presents the least amount of POI shift I can get from my prone with bipod zero.

30 cal and smaller standard case chamberings with a 15 lb rifle and some sort of muzzle device (brake, suppressor) and an optical sight will experience very little POI shift when changing positions if the shooter is good at putting consistent pressure on the rifle. That said, I personally would zero based on the position I most expect to shoot from anyway.

How many tactical shots are taken from a bench with bags LL? Should this be the preferred zeroing method I take it based on your comments above?

Just being argumentative/thought provoking as usual. I'm sure your comments in context have merit, as do mine and criver's.
 
Re: Change in poi?

All,

Just a sidebar, but most of my "scope" shooting over the last few years has been with a TA31F ACOG. I prefer irons to it for a multitude of reasons.

What I see in this design is parallax error, on too many examples of the concept to keep count of. It is not easy to accommodate the parallax error for good results at the sort of distances the ACOG becomes useful, with it's rangefinding/BDC reticle; and, it requires essentially re-zeroing/favoring with each new placement of the head on the stock, unless you've a real good feel for it-not too inspiring for a first round hit. Of course, when parallax is not an issue, it's the fastest way to a distant hit that I've had any experience with.
 
Re: Change in poi?

You'd be surprised what we shoot off of... those straps on the rear bags, like found on the TAB Rear Bag and on the Redman bag, we put over the bipod with them folded up, so we can rest on the rear bag used under the bipod.

We have a large permanent barricade set up, as well, you may have missed that whole live fire Obstacle Course thing we do were we shoot off the concrete culverts, in fact we excel at shooting from supported positions, as well we shoot a fair amount from a sling.

Since you answered my question with a question, how about an answer yourself, how much support side shooting do you do, do you find you have a different point of impact when moving from the right to the left, because shooting around cover is a basic skill, I am sure you practice it every chance you get.

I have a video in front of me shooting an M4 one handed, do you find with your service rifle you practice injuries drills a lot. Loading, unloading, clearing jams with one hand... is it something you even think about.

I have to save, moving through our alternate position course, I haven't noticed any real POI shift, although I think I am bit more realistic in my shooting than most on this board. I don't purport to hold .25MOA in field conditions, so I have a certain basis in reality of what is practical and what is not.

as an FYI, there the video of my dropping my rifle off the roof of the kill house then removing the scope and dropping it, my return to zero is pretty good minus the small shift when the rings weren't torqued properly. Maybe when I go back to TX I can demonstrate how my POI doesn't shift via video.

To note, we find many people shoot differently off different objects mainly because they don't know any better. They either bare their head down harder or use a form of free recoil off the bags, in essences changing how "they" shoot... a gun zeroed shouldn't know any better, a zero should be a zero, if the shooter changes his input to the rifle that can hardly be over looked.
 
Re: Change in poi?

OK, so somehow "Is it normal to have defferent points of impact when shooting from sandbags and then going to a bipod?" got extrapolated into you guys do a bunch of varied shooting down at RO.

What is your one word answer to the original question Frank?

Also, when you are teaching weak hand barricade shooting, what is the distance you are shooting and what constitutes a "hit" so we can extrapolate what your MOA POI variance can be and still be considered a good shot that did not cost someone their life?
 
Re: Change in poi?

THE ONLY TIME that your zero will be different with a "Tactical" weapon is if you have stock problems. Cheap stocks, Savage is notorious for having this problem. Bedding issues. Shooter error. I have seen this problem with a B&C stock. The forend flexes so much that the slightest amount of torque throws your rounds off. With practice they can shoot, but it is a shooter error.

Better stocks like McCree, Manners, and McMillan are more forgiving as far as this is concerned.
 
Re: Change in poi?

BTW, I am not talking about high power shooting. That is Sterling and 9H's realm and I understand the need for different zero's there, I had them when I was shooting in htose comps.

My comments above were just on tactical style rifles
 
Re: Change in poi?

Another set of questions... well okay, I actually have answers, although I am just repeating myself.

The answer is, the shooter is changing his input to the rifle, what JROSE wrote is essentially correct. A rifle doesn't change its point of impact, the shooter effects that...so we consider that a training issue. The original poster, asking the original answer is doing something different to cause the impact shift, especially 2" to 3 inches. It can be taught to remove the zero...

I'm not sure I understand your first line, we don't expect different point of impact shift. For example at 100 yards on the dot targets, anywhere from 1/2" to 1" dots we expect the shooter to hit the target from either side with equal accuracy. In fact we find some people shoot better from the support side, shifts are not expected... hit the 1" dot the same.

The Barricades go from Sitting to Kneeling, to Standing, because of the changes we usually use a 3" Shootin C, but will say, if we just went from sitting to kneeling a 1 to 2 inch dot would be fine, we use the 3" because of the standing and the fact we use 15lbs rifles.

In the kill house, we use a table to shoot off of, a 2" is generally used because of time and the fact we run from the kill house to the bus, to the barricade, to the sewer pipe, to the last barricade... so again a bit more realistic.

Maybe we don't fall into convention expecting things to be how they were once taught. Take the Cold Bore shot, in fact all the books talk about recording your cold bore shot, how your cold bore is always gonna be different because the "gun" heats up and changes its point of impact, well, Leo, bullshit... recent RO training example
2q0otwx.jpg


Not only was the cold bore shot on a 3/4" Dot, we shoot 2 shots together to show... this was shot with a GAP Sniper's Hide edition rifle #22 by Jim there... tell him he has a cold bore shift. When you do things consistently and correctly these myths of the past seem to disappear. If the idea of a rifle heating up was true, the rounds would "walk" not just to the target but across the target.

Shooter errors should not be accepted but trained to a standard, when you push people in that direction its funny how they step up... you can say, Oh ya, the "rifle" will shift from your bipod to your bag, or you can say, no, do it consistently and it won't and the next thing you know it doesn't.

 
Re: Change in poi?

My zero is the same or I scrap rebuild or make it so.I use sand bags and bipods ..

IMHO anyone thats a tactical/longrange shooter should strive to impact target in kill zone with 2 rounds CB and all .
1st round is a sighter unless your lucky round two is the real deal and you better be quick on follow up its the most important outside your comfort zone anything else is play time..

I train myself to be ready for the unexpected...

(edit)
I should add If I cant trust my first round I cant correct my DOPE for 2nd round hit ..

We all have our owm mind hickups and accept some and battle others to overcome..

 
Re: Change in poi?

Pitching in, my more recent shooting has been plagued with inconsistencies and inaccuracies. Enough so that I was beginning to think about packing it in and 'hanging up my spurs' as it were.

Then STP, my shooting partner, intervened with some observations and advice.

Short story long, the problem was me, and it's been quite soluble. Went from about 3MOA to under 1/2MOA at 100yd in about 30 minutes.

The issue was recoil absorption and torque management. Please note that nowhere in that sentence does the word 'control' appear. One does not control recoil, one accommodates it and tries to guide it toward consistency.

LL is dead spot on when he says that poor shooting is due to poor technique. I know this for a fact, brought home by my own recent events.

In my instance, I was bag shooting with riflescope sights. My forward bag was both too hard and provided absolutely no lateral support. The bag was causing upward recoil bounce, and torque was spraying rounds left and right. This was compounded by my erroneous compulsion to allow the rifle to free-recoil, and not paying essential attention to reestablishing the precisely same rifle/bags positional starting point relationship for each shot.

Things were so bad, ladder load testing was completely unable to identify performance differences.

By simply comparing the outcomes of free recoil vs a deliberately harder hold, and establishing a consistent start position, I was able to achieve very significant improvement downrange. Meanwhile, this week; I'll be doing some experimentation redesigning the front support interface to accommodate the rifle more effectively.

Will positional and support differences result in POI shifts? Absolutely.

That's because each variance induces different recoil paths.

The rifle does not shoot alone.

Its recoil characteristics are governed by its support, and each different position and means of support introduces differences that alter the recoil path. It's only significant during the bore transit cycle, and that's only a bitsy instant, but when you consider that the difference in zero elevation adjustment between 100yd and 1000yd is only about 1/2 of a degree, everything about that portion of the recoil cycle is highly significant.

You will likely never eliminate such variances, position to position, but with more attention to NPA, position support and relaxation, and rifle manipulation, they can be significantly minimized.

Greg
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">

Shooter errors should not be accepted but trained to a standard, when you push people in that direction its funny how they step up... you can say, Oh ya, the "rifle" will shift from your bipod to your bag, or you can say, no, do it consistently and it won't and the next thing you know it doesn't.

</div></div>

Accept as fact that the bullet will always go in the direction the barrel is pointed; and, the only excuse for not putting em all right-in-there is you.
 
Re: Change in poi?

One of my basic teaching techniques is the tacit expectation of excellence. One doesn't demand it, one infers that it is simply the minimum acceptable denominator. People will rise to that denominator, often with no actual conscious thought, and that's the way you want it to happen.

Greg
 
Re: Change in poi?

Frank, you've done a great job here of explaining the role of shooter-induced POI error when shooting an accurate rifle/ammo combo with a known confirmed zero in a very "shootable" configuration - heavy rifle, muzzle device affixed, standard chambering.

That IMO cannot be construed to represent the be-all end-all answer when it comes to POI shifts as one changes support types and shooting positions.

Within the context of your shooting and training, the answer is NO, you do not expect a POI shift. Within the broader context, the answer is yes it is most certainly possible.

BTW picking an AR with a muzzle device as a platform for determining if POI shifts occur due to different means of support is another not universal application of the answer of yes or no to the question. My SPR/SDM rifle is as close to Nintendo as it comes - line it up, execute a decent trigger pull, and it shoots where you point it. My 10 lb 30-06 with no brake shooting 200s at 2830 FPS does not afford such repeatability, and while it is the shooter's burden to try to produce repeatable POI, it is easier with some systems than others.

Maybe the correct answer is - the more felt recoil and muzzle movement the system produces and the means of support allows the more likely you will have a POI shift using different positions and the more difficult it is for the shooter to control it. That fact does not change the goal of repeatable POI across multiple positions, but in some cases it is easier to achieve than others. If you want to differentiate that from the static mechanical ability of the rifle and ammo to perform the same then that helps the explanation as well.
 
Re: Change in poi?

Never said anything about a "muzzle device"... some people have them, others don't and frankly I don't think they have anything to do with it.

Driving the rifle correctly is simply that, driving the rifle correctly whether it's a 300WM or 308, or even a 5.56... granted not all rifles are created equal, and some people react differently to recoil, but again, its a person's reaction to that recoil which causes the problems along with bad habits already ingrained to the shooter, hence it's a training issue.

If you support the rifle correctly, you execute the fundamentals to the best of your ability, the rifle will recoil straight back each and every time, thus not causing these deviations. Even during positional shooting which is why we "square' up and not blade to a target, among other reasons. Sure it requires the understanding that the felt recoil will be stronger when it is not supported like in the prone, but you can still drive through that and you will not have the POI shifts one would expect.

Further, we have taken most of the conventional wisdom's of the past and dug down to identify root causes of these problems. Once we identified the cause, we worked to drive through it so it no longer exists, like the cold bore. Its funny no matter what the experience level of the shooter, in our full class the thing we hear more than anything else is, "That was never explained to me that way", why because the books are vague and only give a basic idea of what they are looking for... "straight back on the trigger", what does that mean, well it means you build the finger placement from the trigger back and not the hand forward because there is no way to pull a trigger "straight" back if you have it on the first joint of your finger, or you have the finger nail cocked back or at any other angle but perpendicular to the bore... so once you identify stuff like that your shooting begins to change. Do people shoot very well without these things absolutely, like Greg said many people learn to manage the rifle and the problems better than others, but that doesn't mean you can make that management easier or more consistent. His word management is exactly what we use, to manage the errors in your shooting, both at the shooter and after the bullet leaves the bore. Its all about a management of errors.

But go watch that Hensoldt torture test video, watch my muzzle move straight back with no brake or suppressor... I'm not a big guy, so why is it my muzzle doesn't jump, hop or recoil in an erratic way these other people experience, the answer is explained here in great detail.
 
Re: Change in poi?

Had an ar-15 that would change POI with were I placed the bag on the handgaurd. It was freefloated. I worked hard to make sure it wasn't me. I was sure it was me rocking the rifle on the bag diffrently as were it was positioned. I had another shoot it and it did the same. I sold that rifle.
I notice very little CB shift or position changing cause shifting in POI. A good rifle shouldn't shift much at all if any.
I can always see wind or mirage the biggest factors in POI change. From day to day, temp and barometric pressure change POI further out. Or a cooked round, hot powder.

If POI changes with bags and bipod, and it is not the shooter. I would look at the stock flexing and poor action bedding.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: montana</div><div class="ubbcode-body">

If POI changes with bags and bipod, and it is not the shooter. I would look at the stock flexing and poor action bedding. </div></div>

I've seen this stated a few times, but wouldn't stock flexing/ bad bedding show inconsistencies throughout the rifles performance as a whole, not just switching from one rest to another?
 
Re: Change in poi?

Wow it looks like I stirred up a hornet's nest with this question.
What I believe it was,simply, was me doing something wrong.
I haven't shot prone with the bipod before. I did notice that with the bipod legs in the short (9"?) position I had to lower my head in an awkward position to get a sight picture. When I extended the legs on the bipod it seemed to be too high and very unsteady. I do need more practice- a lot more.
What I saw was that my poi was 2"-3" lower than the poi off bags on a bench.
My rifle is an SPS_Varmint that I mounted in a B&C Medalist stock. I didn't bed the action.
I will do some more from the bench to get a load developed then do my shooting prone with my bipod or a backpack.

What my original question was about was whether it was something like parrallax or if there was something else specific I needed to check.

Jim
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pepperbelly</div><div class="ubbcode-body"> Wow it looks like I stirred up a hornet's nest with this question.
</div></div>

This is nothing....

Next topic you post, ask about <span style="font-style: italic">Spin Drift</span>...
laugh.gif
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JRose</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pepperbelly</div><div class="ubbcode-body"> Wow it looks like I stirred up a hornet's nest with this question.
</div></div>

This is nothing....

Next topic you post, ask about <span style="font-style: italic">Spin Drift</span>...
laugh.gif
</div></div>

Nah! I am in Texas, and at this latitude the coriolis effect of the earth's rotation cancells out the spin drift problem.

Jim
 
Re: Change in poi?

You have much to learn grasshoppper.
You only shoot one direction in Texas?

As to the bedding and stock flex thing. If things are consistant so is the impact, as I see it. If the stock flexs and stresses the action diffrently, impact changes.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pepperbelly</div><div class="ubbcode-body"> Wow it looks like I stirred up a hornet's nest with this question.
What I believe it was,simply, was me doing something wrong.
I haven't shot prone with the bipod before. I did notice that with the bipod legs in the short (9"?) position I had to lower my head in an awkward position to get a sight picture. When I extended the legs on the bipod it seemed to be too high and very unsteady. I do need more practice- a lot more.
What I saw was that my poi was 2"-3" lower than the poi off bags on a bench.
My rifle is an SPS_Varmint that I mounted in a B&C Medalist stock. I didn't bed the action.
I will do some more from the bench to get a load developed then do my shooting prone with my bipod or a backpack.

What my original question was about was whether it was something like parrallax or if there was something else specific I needed to check.

Jim</div></div>

To become a really good shot requires an understanding of what's important to good shooting. What's important is consistency. Consistency is synonymous with accuracy. The concept must be mastered to perfection, in all aspects, if winning performance is the objective.

For you, right now, analysis is the key to your marksmanship development. To zero, that's to say, bring point of aim and point of impact to an intersection, will first require work on sight alignment and trigger control. And, although you can get a steady support from a bipod, you may want to shoot from the bench with a sandbag support, since it's an easier support to muster, allowing full concentration on sight alignment and trigger control.

Once you've got consistency with the principles of marksmanship, as evidenced by small groups, from which a good zero can be set, then other positions/supports can be studied. This methodical approach to marksmanship development will help you to trouble shoot for any inconsistency which is undermining your results.
 
Re: Change in poi?

A muzzle device is only going to work once the bullet is heading downrange.

Inertia, recoil, and shooter's body reaction are what will govern muzzle movement during bore transit. That deviation is an integral part of determining each individual shot's POI. It MUST be consistent, and when how close that consistency becomes will govern how tight the shooter (not the gun) shoots.

A well designed stock (like the straight line concept around which the AR stock works so well) and a proper/consistent shooter position/grip will dictate how consistently the muzzle will deviate during bore transit. That deviation is the true measure of POI consistency in positional shooting.

Anything else is snake oil.

Greg
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: montana</div><div class="ubbcode-body">You have much to learn grasshoppper.
You only shoot one direction in Texas?

As to the bedding and stock flex thing. If things are consistant so is the impact, as I see it. If the stock flexs and stresses the action diffrently, impact changes. </div></div>

Yes we only shoot one direction in Texas- downrange. That shooting over your shoulder thing is for pistols on horseback only. I will work on the load workup from the bench, and if I can get consistant small groups there I will work on my position shooting.

Jim
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">A muzzle device is only going to work once the bullet is heading downrange.

Inertia, recoil, and shooter's body reaction are what will govern muzzle movement during bore transit. That deviation is an integral part of determining each individual shot's POI. It MUST be consistent, and when how close that consistency becomes will govern how tight the shooter (not the gun) shoots.

A well designed stock (like the straight line concept around which the AR stock works so well) and a proper/consistent shooter position/grip will dictate how consistently the muzzle will deviate during bore transit. That deviation is the true measure of POI consistency in positional shooting.

Anything else is snake oil.

Greg</div></div>

Your post pretty much sums up how it's possible to stack up bullets. Yet, as easy as it is for me to understand the importance of recoil manipulation, most folks don't get it. They are oblivious to the importance of position consistency to good shooting. The elements and factors of a steady position seem to be too abstract for most folks to get a grasp of it. The other day I put 17 rounds out of 20 in a 3/4 inch group with irons from prone with sling and irons. Of the 3 misplaced rounds, two went out to the 9 ring and the other went through the 8 ring, all on-call.
It had nothing to do with anything other than me just not building the position to perfection for every shot. I just got lazy. Thing is, most folks would not be able to attribute such errors to position, to understand the consequence that a less than perfect position fosters.
 
Re: Change in poi?

I did the same with a .22LR at 50yd, 7 of ten in a nicely centered hole about nickel sized, and the other three just as tight 2" away at 1:00 o'clock.

Clearly a cheek weld issue, and not too bad for my first shots with irons in about 2 years. I have subsequently adopted a 'nose weld' with my nose up against the sight base. With a .22lr there's no recoil to deal with, and this weld is definitely repeatable.

I've started taking it out to 100yd, and the combination of a peep that shows about a 100ft field of view and a relatively small target have still got me chasing my tail, but it <span style="font-style: italic">will</span> come with decent practice. It's just an old friendship that needs some more cultivation.

Greg
 
Re: Change in poi?

LL,

Today, I shot for grins and giggles. Standing, my corrected zero, confirmed by a blind plot and call exercise, was 6 quarter minute clicks up from bottom and 2 quarter minute clicks right from mechanical zero, shooting at 100 yards. Sitting and prone, the correct zero was 10 clicks up and mechanical on windage. The different zero for each of these positions was expected, as I'm an experienced shooter; and, I know the recoil from standing will not be of the sort it will be from prone or sitting. It can't be, since I can't physically hold the rifle in the standing position as I do to control the rifle until recoil subsides in the sitting or prone position. BTW, light, temperature and wind remained consistent during all strings.

My point is this, having a multitude of zeros is what it is. I don't think having a different zero for any change made to position and/or support needs to mean the shooter is not maintaning a proper position, although it could.
 
Re: Change in poi?

I must be lucky as my 100 yard zero is the same as is my dialed dope whether shooting right or left handed prone or sitting or kneeling or shooting off objects. Don't know about standing as I am not that good shooting prone to shoot a group
wink.gif
I don't use irons though. That is with a scope.
 
Re: Change in poi?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">I must be lucky as my 100 yard zero is the same as is my dialed dope whether shooting right or left handed prone or sitting or kneeling or shooting off objects. Don't know about prone as I am not that good shooting prone to shoot a group
wink.gif
I don't use irons though. That is with a scope.</div></div>

I think you meant you're not good enough to shoot a group standing, didn't you?

My prone, and sitting zeros are often the same at a given distance. When they're not they're close. But, even when zero's are the same for various positions at any given distance/condition, don't count on it being permanent, as any condition change-whether you're shooting with a scope or irons will effect your understanding for where the gun's pointed.
 
Re: Change in poi?

Saturday after the match a shooter showed up that wanted to verify his zero and dope on the KD range as I was setting up to shoot some Service Rifle practice. After 3 shots he had his zero verified at 200 yards with a nice pinwheel X.

I blew the spotter out, offhand, in a 10-15 MPH cross wind with my first shot. After the target repair I fired 3 more Xs in a row.

Friday I group tested (5 shot) at 600 yds 3 different Palma loads. Sling, coat, and irons they all produced 2" of vertical dispersion and 6" of horizontal dispersion as I was not correcting for the wind shooting alone at 600. After that session I was convinced I had a dead nuts 600 yard elevation zero. Fast forward to 9a Saturday morning. Same rifle, range, and loads. I fired 3 9s out the bottom before I got the sense to turn the sight knob up 3 clicks.

Sunday for the Palma event I ran my NRAWC elevation zeros for my first shots at 800, 900, 1k. Even though I had gone down 2k in elevation to this range, all 3 zeros were 1 1/4 MOA high. Full value changes were made immediately so that the second sighter came up in the X ring.

So much for having a known zero.

Shooters like Skip and I know that holding fast on what a shooter believes to be a "known zero" and ignoring what is happening in real time is a good way to shoot a lower score. Sometimes we forget that, like I did Saturday AM.