Wandering zero

[joeb33050]

Sometimes when shooting from the bench, at 100 yards, at target dots on a ~24" X 24" paper, the zero moves as I go from target to target. First target might show a zero 2" directly below the dot- Second dot maybe 4" to the right of the first, zero is now 3" below and 1" right of the dot. Etc. The group centers move as the gun is aimed at different dots.
Does anyone know why this is, and/or how to eliminate the effect??
Thanks;
joe b.

[44man]

It is caused by YOUR shifting of position and hold to align with another spot. Something is changing, bag pressure, hand or cheek pressure or how you see the target through the scope or sights.
Even the movement of the sun over time can shift the POI. Try an experiment. Take a scope and mount it to a board or mount a rifle in a rest. In the early morning, sight on a target at about 200 yd's. Never touch the scope all day but look through it every 15 minutes and record where the cross hairs are at each time.
When the day is over you will scratch your head and wonder how you can hit anything at all. [smilie=1:

[BIGGUNGOBOOM]

what sort of rifle is it???? most likely their is a lot of end pressure and side pressure on the barrel. as you continually shoot the gun it warms up and push's against the stock. I now and always will float and bed a gun from now on before even shooting it for the first time. It really dose make a difference.

[mooman76]

You are having some kind of inconsistancy. Like 44man and biggungoboom said. What kind of gun and sights would be a help but there are many factors it could be. My gues would be like 44man said you are changing your position and site picture causing this. That's one reason I don't like peep site that much because I have a tendency to do this more with those sites than others.

[Larry Gibson]

Joe

Are we to assume you are shooting the same load each time?

Larry Gibson

[JIMinPHX]

Could be your grip, barrel heating, barrel/action to stock fit, or change in spring pressure if it's a tube fed gun. Something is changing when you shift to the other target. Look for any little thing that may be different.

[Echo]

I think it's the nut that holds the stock...

[joeb33050]

This happens with about any gun, shooting from the bench, same load. It has happened with great regularity for many years, with rifles from Rem 40X to C. Sharps 1875. And it happens to many other shooters, none of whom has been able to explain why or how to fix it. If you shoot a lot of BR, you'll know what I'm talking about. This makes it difficult to shoot good SCORE targets. For examples, see the small groups shot at 200 yards by ASSRA guys on SCORE targets, where the tiny group would easily fit in the 25 ring, but is offset and not a 250.
joe b.

[bullshot]

If you have done any position shooting you know what natural point of aim is. Where you sight the target, close your eyes reopen eyes, the sights should be in the same place. If not you are forcing the rifle to point where you are sighting. When the shot breaks the rifle relaxes changing the point of impact. This can change each and every time you sight. This is only one reason. As others have said lighting can be a major factor as well as head position, grip etc.

[45 2.1]

Sometimes when shooting from the bench, at 100 yards, at target dots on a ~24" X 24" paper, the zero moves as I go from target to target. First target might show a zero 2" directly below the dot- Second dot maybe 4" to the right of the first, zero is now 3" below and 1" right of the dot. Etc. The group centers move as the gun is aimed at different dots.
Does anyone know why this is, and/or how to eliminate the effect??
Thanks;
joe b.

I've noticed thru the years that light conditions, varying wind and rifle management (the nut behind the butt) cause these things. Eliminate those variables and things get a lot better.

[Wayne Smith]

Yeah, but if we eliminate the latter it's no fun any more!

[45 2.1]

Yeah, but if we eliminate the latter it's no fun any more!

I have several rifles that have that problem of not being fun to shoot anymore. Pure accuracy has its rewards, but at a cost.

[Char-Gar]

I agree with Bullseye and others that it is caused by shifting of the rifle between shots or groups. It is a freqent occurance and not rare at all. Strange as it my seem, I can shoot better groups, when I lock down on the stock and shoot rapid fire, running the rounds through the magazine (bolt gun). When I take my time between shots, look the the spotting scope and load single shot the groups open up a smidge and the POA will somtimes wander a bit. Nothing extreme, but noticeable.

I try my best to cose my eyes after acquiring the sight picture to see if there is any shift when I open them. If there is any shift, I am horsing the rifle some way and it is not solid as I would like. Like Bullseye, I learned this in years of four position shooting with a tight sling. It is one of the basics.

Times have changed and many of todays shooters did not learn the basics of riflecraft when they started. Few today have seen the crosshair of a hi-mag target scope, jump with each heart beat transfered through a tight sling and a rock solid prone position. You try and time you shots between the beats of your heart. Learning to relax, get rid of tension, stray thoughts and the like to slow your respiration and heart rate and that shows up on the target. When a fellow gets serious about winning over other good shots with good equipment. it becomes a head game. The fellow that picks up all the marbles is the one who has best control over his head.

Lots and lots of recreational shooters go to the range for fun and fellowship and don't truly have their heads into what they are doing. Riflecraft is made up of basic learned skills, that are practiced until they become rote. After that, what in in your head when you press the trigger will make or break the day at the range.

At age 66, I can still take a 60 year old rifle, with click adjustable receiver sights, shooting good cast bullets and go to the range and stomp guys 30 years younger with $5,000.00 worth of rifle, scope and shooting crap. I don't shoot the breeze with them before, during or after the shooting. I just pack up, go home, leave them to ponder why I am so unfriendly and how come I had such a lucky day.

The rifle is a jealous mistress who demands all of your attention. It is always fun? No! It is sometimes work? Yes! But forcing the cold and inaminate rifle to bend to your will is also rewarding.

Please pardon the long rambling post, but these sort of threads start me to thinking and is not always a good thing.

[sundog]

"At age 66, I can still take a 60 year old rifle, with click adjustable receiver sights, shooting good cast bullets and go to the range and stomp guys 30 years younger with $5,000.00 worth of rifle, scope and shooting crap. I don't shoot the breeze with them before, during or after the shooting. I just pack up, go home, leave them to ponder why I am so unfriendly and how come I had such a lucky day."

Charles, that's devious and cruel. I LOVE IT!!! And, a big 10-4 on your heart beat comments.

[felix]

Yes, Charles, you are so correct. It is a head game. The objectives MUST be commensurate with the goals of the shoot. This is the principal reason why I do not shoot competitively any more. For example, the goal is to win a match and/or have fun collecting statistics. But, the objective is making a one hole group or killing each and every beer can dead center. Invariably, in Charles' round about way "that's not taking care of business." ... felix

[Larry Gibson]

This happens with about any gun, shooting from the bench, same load. It has happened with great regularity for many years, with rifles from Rem 40X to C. Sharps 1875. And it happens to many other shooters, none of whom has been able to explain why or how to fix it. If you shoot a lot of BR, you'll know what I'm talking about. This makes it difficult to shoot good SCORE targets. For examples, see the small groups shot at 200 yards by ASSRA guys on SCORE targets, where the tiny group would easily fit in the 25 ring, but is offset and not a 250.
joe b.

Joe

With that being the case then as most are mentioning here the problem is when you shift from one dot to the next you are not consistant in your position, your grip of the weapon and/or the way the weapon lays on the bags. Bullshop mentions "natural point of aim" and he is correct. When you shift the rifle to a different target you shift the rifle and rests and must also shift your position. Consistancy is the key.

Larry Gibson

[runfiverun]

stated another way yet, if you are changing targets. change, then shoot.
don't swivel or just swing over to it.
i have learned this one the hard way $$$$.

[nvbirdman]

Parallax error.
While looking through your scope at the target, move your head around a little bit. If the crosshairs move around on the target that is parallax error. I think the scope manufacturers set the scopes up to be parallax free at 150yds.

[Echo]

Times have changed and many of todays shooters did not learn the basics of riflecraft when they started. Few today have seen the crosshair of a hi-mag target scope, jump with each heart beat transfered through a tight sling and a rock solid prone position. You try and time you shots between the beats of your heart. Learning to relax, get rid of tension, stray thoughts and the like to slow your respiration and heart rate and that shows up on the target. When a fellow gets serious about winning over other good shots with good equipment. it becomes a head game. The fellow that picks up all the marbles is the one who has best control over his head.


Top shooters have learned, sometime unconsciously, to break the shot between pulse beats. True story.

[HABCAN]

What Chargar said, with a hat-tip to the other posters! BTDT.

[joeb33050]

When shooting from the bench, the group center moves as I go from dot to dot. The targets I’m talking about are 24” X 24” pieces of paper with sets of dots spaced ~ 4” apart, so a set might be, from the left edge of the paper, at 4”, 8”, 12” 16” and 20”. Sets might be spaced 4” apart in height.
My impression is that generally the group center moves in the direction the gun is moved. If the rifle is moved left to shoot at a dot to the left of the last one, the group center will move to the left. This is merely an impression, not any kind of rule. Sometimes the group center moves up or down when the gun is aimed at another target.
I’d like to know why this happens, and how to cure it.
I have no guns with “bench rest” 3” wide forends.
I use a Hoppes front rest with a Stoney Point Universal Front Bag, (4.75” L X 2.5” H X 2” W), and a Protektor rear bag. The front bag is attached to the Hoppes rest with double-sided tape and the Velcro holder things. The front rest is free to turn left and right, the top piece is free to rotate on the shaft. Everything else is locked down. Coarse elevation adjustments are made on the Hoppes front rest; fine elevation adjustments are made by sliding the gun forward and backward.
Clearly, windage adjustments are made by moving the rear bag left and right.
I put baby powder on both front and rear rests frequently, to keep
I have considered getting one of the very expensive bench rests with the precision windage and elevation adjustments, but so far have been able to control myself.
First, the windage adjustable front rest, it seems to me, puts “different” forces on the forend as it is adjusted right and left. Torques the forend.
Second, I can shoot small groups with the rests described above, consistently shooting under 1” five-shot 100 yard groups with rifles capable of that, so neither my rests nor my procedure is grossly wanting. I think.
I took my question to some forums, and got a variety of responses. This response let me know that my experience is not unique/I may not be nuts:
“It's a common problem when shooting at multiple bull targets. That is one thing that makes shooting a 250 on the 100 yard ASSRA bench target more of a challenge then one would think it should be. I always suspected it had something to do with the position of the rifle on the sandbags but it could also have something to do with how the rifle is held from the slightly different positions. It also could be that wind conditions change as the target is being shot. I have been shooting single shots a long time and I don't know for sure. Maybe some of the others who are more expert then I at rest shooting can give you the answer. I would like to hear from those that shoot "free recoil" to see if that helps.”

The more credible of the suggestions:
“…after each shot, move the rifle back and forward in your bags. This will settle the rifle in the bags the same each time. I move the rifle forward and aft about three time each time, just before I get ready fire.”

“…slide the rifle firmly in the bags to reposition when moving to a new target. After pushing down on the rifle when sliding it in the bags after aiming at the new target; confirm the rifle is sitting squarely on the bullseye without any body pressure on the rifle.
…Rule number one is to ensure the rifle is sitting in the sandbags pointing perfectly at the new target's bullseye before I assume the firing position. And that the position is stabilized by walking the rifle in the bags to ensure it is sitting perfectly before you assume your bench shooting position.
…the next best rule is to ensure you pull straight back on the trigger to prevent any side torque from slight pressure from pulling on the side of the trigger…
…If you don't walk the rifle into the bags it will be following the same path established from the recoil from shooting the previous targets; and you can get the rifle recoiling slightly off center until it re-establishes a realignment of the sandbags on subsequent recoils. “


These mean to me that after shooting one group, re-set the rests and “mash” the gun into the bags to get it settled in and aimed at the next dot. This rather than looking through the scope and moving the rear bag to get aimed at the next dot. A new beginning, a new set up, for each dot shot at.

Anything I missed? Anyone?
Thanks;
joe b.

[Char-Gar]

Joe - Here is what I do and I have very little problem with wandering POA. This is not to say I had not experienced it, but not often. It happens when I get in a hurry or are fatigued.

1. I don't shoot at multiple dot targets. My targets are a 4 inch black bull with a 1" white center on 8 1/2 by 11 paper. I just use a new sheet for each group. I have many, thousands of these targets, having run them off on the back of other office documents in the Risography machine. Yep, I am cheap.

I don't use a scope often, but when I do, I find it easy to divide the bull into four equal quarters with the cross hair. That is what I pay attention to and not the white center dot. The four quarters should be equal in size and the cross hairs straight up and down. No mater what size target or shape of target, when using a scope I quarter the target.

2. I re-lay the rifle for each target. I dont just shift around on the bags. I will move either or both (front and rear) bags if necessary. I do not want the forend at an angle on front bag. Both bags must be parallel to each other and the target.

I make certain the sights are propertly aligned on the target. I then sit up and lean back into the stock and recheck the sights. The sight picture should be the same as it was before I sat up. If not then something is wrong and I make corrections.

3. I them pull the butt tightly into my shoulder with the strong hand on the grip and use the other hand to massage the rear bag a smidge for exact sight alignment. I relax the rest of my body for tense muscles can pull on he rifle one way or another. the ony muscle tension at all should be in the shooting arm and hand. Every other part of the body, including the head and neck should be relaxed. If you shove you face into the stock, that can cause problems. Just lay your cheek on the stock.

4. I place my strong hand thumb on top of the grip or on top of the receiver tang and squeeze the trigger. My thumb and trigger finger form a kind of vise or clamp as I press the trigger. These keeps me pulling the trigger straight back and when I broke the code on this, my groups showed immediate improvment. That was about 1960.

5. Of course there is breath control, clearing of the mind and all of that. Any stray thought that breaks the concentration will result in a bullet not being perfectly placed.

6. In a rifle of any weight, shooting cast bullets at less than 2,000 fps, there should not be much need to re-lay the rifle between shots. Move the rifle as little as possible between shots.

All of this powdering the bags, sliding the rifle back and forth and mashing the foreend down into the bags seems to me like a bunch of nonsense. Tis true a flat forend is easier to manage on the bags than a round or oval one. But it is just easier that's all. Precision shooting can be done with any forend configuration.

Now, I have never had a lesson on bench rest shooting or read any advice of experts. I may be doing it all wrong according to the experts and their theory. But I have been a student of riflecraft for 55 years and the above works well for me.

Consider the above for what it worth to you, in whole, in part or disregard it all. I don't have a dog in the fight and don't give a fig if other think I don't know what I am doing. I may not, but I can shoot small groups with little or no wandering POI. Isn't that what this thread is all about?

Equipment? I have a fairly light weight Lyman front rest with a sand filled leather back with a U shaped indent on the front. The rear is a sand filled leather bunny ear bag. The spotting scope is a late 40's vintage Argus. I am not an equipment junkie! A fellow can either shoot a rifle or can't shoot a rifle. He cannot buy his way into riflecraft and marksmanship. Good equipment will give a good marksman the edge over another good marksman, but expensive equipment will not a good marksman make.

Oh yes... I have no idea what "free recoil" is all about. But, if that means the rifle butt is not tightly against the shooting shoulder, I don't think much of the concept.

[felix]

Free recoil is used my most BR shooters; in worst case, the trigger is squeezed with index finger and thumb against back of trigger guard. We are not over the 6PPC class of recoil in a 10.5 pound gun with square bottom 3 inch forearm. ... felix

Pretty good introduction: http://www.youtube.com/watch?v=7I-c-HSHFas&NR=1

[Char-Gar]

Felix.. I watched the video a couple of time. I like his emphasis on consistancy and keeping your head down in shooting position between shots. I noticed very little pressure against the shoulder and he laid his shooting thumb alongside the stock.

I am assuming he has a trigger pull that measures in ounces and not pounds. I could not control a heavy 5 lbs military trigger that way. The pressure on the trigger would move the rifle back out of position without the counterpressure of the thumb/hand on the grip and the butt firmly against the shoulder. I can see how it works for him on his rifle.

I liked his emphasis on relaxing the body and the bag for the hand is a neat idea I must try. I never thunk of that.

I tried putting my thumb behind the trigger guard and squeezing the trigger against the counter pressure of the thumb once. The rifle was a 8 lbs 375 Holland and Holand and I damn near broke my thumb.

Anyway..thanks for the link..it was informative and interesting.

[felix]

There is not a trigger on the liine more than 2 ounces. The ones that are over 2 ounces are typically shot using some shoulder pressure and using the squeeze technique. Those are the folks typically having fun at 200 yards rather than shooting for the top gun position in that sport, because their main sport could be 1000 yard competition which requires a completely different gun. A gun like 35 pounds, 284 or better, usually 308, having a case capacity of 80 grains or even more. Not to mention the 50 cals gaining favor at some 1000 yard shoots. ... felix

Keep in mind, Charles, all of these guys who go to win competition are beyond the guns and ammo game, and are nothing more than fancy clothed weather men, and hopefully some women one of these days. Every once in a while a real shootin' woman shows up, but usually she would be a wife or daughter of a "famous" weatherman. ... felix

[Char-Gar]

I would like to try my had at 1,000 yard benchrest shooting, but it would be with cast bullet. Lee Jurris is deep into 1,000 yard shooting and I have vowed to kick his tail with cast bullets some day. Some day..being the key phrase. I doubt Lee nor I will live long enough to see the match.

I have fired 1,000 yards prone at Camp Perry with a Winchester 70 target rifle (30-06) and a NM Garand. I like that "fine and far" shooting.

[mainiac]

[QUOTE=felix;526102]There is not a trigger on the liine more than 2 ounces. The ones that are over 2 ounces are typically shot using some shoulder pressure and using the squeeze technique. Those are the folks typically having fun at 200 yards rather than shooting for the top gun position in that sport, because their main sport could be 1000 yard competition which requires a completely different gun. A gun like 35 pounds, 284 or better, usually 308, having a case capacity of 80 grains or even more. Not to mention the 50 cals gaining favor at some 1000 yard shoots. ... felix

Keep in mind, Charles, all of these guys who go to win competition are beyond the guns and ammo game, and are nothing more than fancy clothed weather men, and hopefully some women one of these days. Every once in a while a real shootin' woman shows up, but usually she would be a wife or daughter of a "famous" weatherman. ... felix[/QUOTE Felix, I had an occation to be a weather man a few times in br,,,, and loved it!!! But when the hot barrell dies,and a man cant afford to find another, what does he become then?I KNOW,I KNOW, a retired br shooter..........sad. Someday,im going to start buying barrells again,,,,looking for THE hot one!

[felix]

Nah, Mainiac, don't do it! Let memories be memories. At our age we have nothing to prove because we have been there and done that. We already know what we can do, and what our limitations are. However, for fun, though, show up at a meet sometime. I guarantee you that a gun will be provided upon the asking. Thataway you won't have a hunk of metal to put back into the closet when you get home. ...... But, on the otherhand, take what you have and make a cast gun out of it. Any worn out barrel (throat, not barrel) will shoot cast well because it had already been "freebored". ... felix