There seems to be much confusion regarding just what purpose an adjustable rib has on a guns POI. Many believe that if you adjust ONLY the rib up or down, you can change the guns POI. This simply is not true. Here is how it really works. If you mount a gun with an adjustable rib and the beads line up in a "figure 8" for you and you pattern it at, say 13 yards, lets say it shoots 2" high. Now you adjust the front of the rib a couple of notches lower, remount the gun, and look down the rib. You will notice the front bead is gone, and you are not able to "figure 8" the beads properly. Don't change anything else, and just shoot the gun mounted as it is, with your cheek pressed to the comb as you normally do, at the pattern board, just as you did before. You will notice the pattern HAS NOT changed a bit. It is still 2" high at 13 yards. Now, RAISE THE COMB enough so that you can comfortably "figure 8" the beads again by sighting down the rib with your cheek in its normal position on the comb. Shoot another pattern and you will notice your pattern is NOW significantly higher than it was before you raised the comb. You need to raise or lower the comb to get your desired POI, and THEN ADJUST THE RIB to get your desired sight picture. I hope this helps clear up some of the mystery that surrounds adjustable ribs when it comes to POI.......Dan Thome (Trap2)
THE TRUTH ABOUT ADJUSTABLE RIBS
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Trap2
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Ed....
Thank you for explaining it a little clearer to these non-believers than I did.
221...
My point exactley, in the K-80 adjustment, you are essentially bending the barrel to get the POI you want, are you not?. "Raise or lower the comb, BEND THE BARREL, or adjust the chokes" to change the POI.
MIA...
Let's ask Vickie at Keensites directly. Vickie, if I put a 60/40 Keensites rib on my gun and change nothing else, will it automatically shoot 60/40 or must I adjust my comb to get the proper sight picture to achieve that POI?
Along the same line, let's pose this theory to Dennis, at NCP, Bruce, at Bowen Guns, Roger Eubanks, at Eubanks ribs, etc. Will any of you care to weigh in on this subject? Does changing only the adjustable rib have any effect on POI, or must the comb be raised or lowered?
buzzgun....
You're right..I'm probably a troll. Your mind is obviously made up, so why in the world would I want to confuse you with plain facts?
Dan Thome (Trap2)
Thank you for explaining it a little clearer to these non-believers than I did.
221...
My point exactley, in the K-80 adjustment, you are essentially bending the barrel to get the POI you want, are you not?. "Raise or lower the comb, BEND THE BARREL, or adjust the chokes" to change the POI.
MIA...
Let's ask Vickie at Keensites directly. Vickie, if I put a 60/40 Keensites rib on my gun and change nothing else, will it automatically shoot 60/40 or must I adjust my comb to get the proper sight picture to achieve that POI?
Along the same line, let's pose this theory to Dennis, at NCP, Bruce, at Bowen Guns, Roger Eubanks, at Eubanks ribs, etc. Will any of you care to weigh in on this subject? Does changing only the adjustable rib have any effect on POI, or must the comb be raised or lowered?
buzzgun....
You're right..I'm probably a troll. Your mind is obviously made up, so why in the world would I want to confuse you with plain facts?
Dan Thome (Trap2)
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What's not being said here? If you replaced your bead with a much taller bead and used the top for aiming, the POI will change without changing the comb. In Buzzs example, the top of the Pepsi can will lower the POI in the same way. You would change the angle your eye is looking over said bead or Pepsi can by raising or lowering the front of the gun in relation to target. Hap
Solution is at hand and Dan T. is doing it the correct way. Get a DB81, just like the one I have for sale, with a fixed rib, and adjust the comb to make it shoot where you want it to and stop swetting the rib issue. Works every time. You cant buy a better trap gun. Tom Ward
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Ahahaha..........youse guys are all nutz. Point of impact never changes relative to the gun. Point of aim is what changes.
The only one that changes POI is the K-80 lower,as as stated by bending the barrel. I believe the Browning ST-100 does a similar thing.
All the rest of this crap is simply changing where you look, the projectile(s) still go to the same place relative to the gun.
(Halfmile ducks)
HM
The only one that changes POI is the K-80 lower,as as stated by bending the barrel. I believe the Browning ST-100 does a similar thing.
All the rest of this crap is simply changing where you look, the projectile(s) still go to the same place relative to the gun.
(Halfmile ducks)
HM
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Dan,
According to YOU, POI can only be adjusted by raising or lowering the comb. Also according to YOU, raising or lowering the rib in any way is only for the purpose of giving you the sight picture you want. It has no effect on POI (according to YOU).
OK, so using YOUR method, I'm going to go step-by-step through an adjustment process.
Let's suppose that my gun is shooting too low to suit me. So, according to you, I raise the comb to raise the POI to my desired height. OK, so far so good. EXCEPT, that now I am not seeing my Figure 8 with my beads like I was before. I am seeing waaaaay too much rib. So, in order to get back to my desired Figure 8 sight picture, I lower the front end of the rib to give me my desired Figure 8 sight picture. However, when I shoot the gun again, I find that now the POI has raised even further due to the lower front end of the rib. So the gun is now shooting TOO HIGH. So now I lower the comb again to lower the POI, but that results in not seeing the FIGURE 8 sight picture. So, using your method, I keep going back and forth, back and forth, like a dog chasing his tail.
The only way to get it adjusted properly to have BOTH the desired POI and the desired sight picture is to realize that changing EITHER the comb height or the height of the front of the rib is going to change the POI. Therefore, the correct way to raise the POI and still keep the same sight picture is to make 1/2 the POI adjustment by raising the comb and the other 1/2 of the POI adjustment by lowering the front end of the rib. That will give me the raise in POI which I wanted while keeping the same sight picture.
Easystreet
According to YOU, POI can only be adjusted by raising or lowering the comb. Also according to YOU, raising or lowering the rib in any way is only for the purpose of giving you the sight picture you want. It has no effect on POI (according to YOU).
OK, so using YOUR method, I'm going to go step-by-step through an adjustment process.
Let's suppose that my gun is shooting too low to suit me. So, according to you, I raise the comb to raise the POI to my desired height. OK, so far so good. EXCEPT, that now I am not seeing my Figure 8 with my beads like I was before. I am seeing waaaaay too much rib. So, in order to get back to my desired Figure 8 sight picture, I lower the front end of the rib to give me my desired Figure 8 sight picture. However, when I shoot the gun again, I find that now the POI has raised even further due to the lower front end of the rib. So the gun is now shooting TOO HIGH. So now I lower the comb again to lower the POI, but that results in not seeing the FIGURE 8 sight picture. So, using your method, I keep going back and forth, back and forth, like a dog chasing his tail.
The only way to get it adjusted properly to have BOTH the desired POI and the desired sight picture is to realize that changing EITHER the comb height or the height of the front of the rib is going to change the POI. Therefore, the correct way to raise the POI and still keep the same sight picture is to make 1/2 the POI adjustment by raising the comb and the other 1/2 of the POI adjustment by lowering the front end of the rib. That will give me the raise in POI which I wanted while keeping the same sight picture.
Easystreet
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I see it as rifle fundamentals being applied to shotguns. Sights are for precisely placing bullets. Beads are for reference when wing shooting, it's not so precise. Or better it's not AS precise. With a rifle you may move your head around (slightly) to get your eye in place then move the gun around to put it on the target. Having your face so firmly planted on the comb isn’t nearly as big a concern as it is with a shotgun. Mostly because you’re usually shooting at a stationary target.
For so many years shotguns have had a rib fixed to the barrel (maybe), and the stock was fitted to place the shooters dominate eye behind that rib (or plain barrel) so's the pattern's impact was where needed. I've seen some pretty funky looking <i>try-guns</i> used as a pattern after fitting it to the shooter.
Then comes to market adjustable ribs and adjustable combs (although not in that order). And different methods of making the gun shoot where you want it to along with them. For me it has always been a teeter totter center pivot rib with notches on either end. So I put the rib flat or maybe the front one notch down and the rear one notch up. Then I adjust the comb so I see a perfect fig.8 and I can mount it with eyes closed and when I open them it's perfect and it's repeatable. Then I shoot it.
If I think I need to go higher I'll go another notch down in front and up in back. Then go through readjusting the comb as described above, and then shoot again. Now if I find I need to go a little higher but a whole notch may be too much, I'll raise the comb and put some rib in between the beads until it shoots where I want it to.
If it still wasn't shooting high enough and I've moved the front down a whole notch, but that made it too high. I'll move the front back up the notch and then adjust the comb so I have some space between the beads to get the POI height I want. In other words I'd never have a sight picture were the beads were less that a fig.8, I'd rather see space between them than put one behind the other. I believe it provides for a better view down range.
Something that has barely been touched on is the fact that we have ribs that adjust like described above, and ribs where only the front moves up and down. And others that stay put but bend the barrel up. All of which effect how you adjust them and how much difference they make.
I now have a gun with a rib that only adjusts up and down in the front, so I'll have to work with it to figure out where I want it. But for me it's the comb that makes the difference, not the front bead. However I understand the other side. cls
For so many years shotguns have had a rib fixed to the barrel (maybe), and the stock was fitted to place the shooters dominate eye behind that rib (or plain barrel) so's the pattern's impact was where needed. I've seen some pretty funky looking <i>try-guns</i> used as a pattern after fitting it to the shooter.
Then comes to market adjustable ribs and adjustable combs (although not in that order). And different methods of making the gun shoot where you want it to along with them. For me it has always been a teeter totter center pivot rib with notches on either end. So I put the rib flat or maybe the front one notch down and the rear one notch up. Then I adjust the comb so I see a perfect fig.8 and I can mount it with eyes closed and when I open them it's perfect and it's repeatable. Then I shoot it.
If I think I need to go higher I'll go another notch down in front and up in back. Then go through readjusting the comb as described above, and then shoot again. Now if I find I need to go a little higher but a whole notch may be too much, I'll raise the comb and put some rib in between the beads until it shoots where I want it to.
If it still wasn't shooting high enough and I've moved the front down a whole notch, but that made it too high. I'll move the front back up the notch and then adjust the comb so I have some space between the beads to get the POI height I want. In other words I'd never have a sight picture were the beads were less that a fig.8, I'd rather see space between them than put one behind the other. I believe it provides for a better view down range.
Something that has barely been touched on is the fact that we have ribs that adjust like described above, and ribs where only the front moves up and down. And others that stay put but bend the barrel up. All of which effect how you adjust them and how much difference they make.
I now have a gun with a rib that only adjusts up and down in the front, so I'll have to work with it to figure out where I want it. But for me it's the comb that makes the difference, not the front bead. However I understand the other side. cls
Now I am very confused!!
I have a K-80 w/o an adjustable comb and Chris Maest told me the same thing about how it was designed to bend the barrel so the sight picture is not changed.
BUT... when I attempted to lower the POI i ended up seeing a totally different sight picture. I now see a ton of space in between the beads so I really don't think the barrel is being bent rather the front of the rib is raising thus creating space between the two beads.
So I guess what I am asking is because I do not have an adjustable rib, i can move the rib back to a fig. 8 and it will still shoot exaclty where it was when there was a space BECAUSE I don't have the adjustable comb..
I tend to disagree with this.
I read Rolland's book and I thought what he said is you make POI adjustments 3 ways. 1. Raise/lower the rib. 2. Raise/lower the comb. 3. Raise/lower BOTH in opposite directions.
If you raise the rib and raise the comb there will be no adjustment to the POI. If you raise one and lower the other, you will DOUBLE the amount of POI.
Set your comb where you are comfortable THEN lock it in. Then raise/lower the rib to adjust your POI and DO NOT worry about how the beads line up.
That is my take, please advise and correct me if I am wrong.
JA-
Maybe Rolland can come on and give his take.
I have a K-80 w/o an adjustable comb and Chris Maest told me the same thing about how it was designed to bend the barrel so the sight picture is not changed.
BUT... when I attempted to lower the POI i ended up seeing a totally different sight picture. I now see a ton of space in between the beads so I really don't think the barrel is being bent rather the front of the rib is raising thus creating space between the two beads.
So I guess what I am asking is because I do not have an adjustable rib, i can move the rib back to a fig. 8 and it will still shoot exaclty where it was when there was a space BECAUSE I don't have the adjustable comb..
I tend to disagree with this.
I read Rolland's book and I thought what he said is you make POI adjustments 3 ways. 1. Raise/lower the rib. 2. Raise/lower the comb. 3. Raise/lower BOTH in opposite directions.
If you raise the rib and raise the comb there will be no adjustment to the POI. If you raise one and lower the other, you will DOUBLE the amount of POI.
Set your comb where you are comfortable THEN lock it in. Then raise/lower the rib to adjust your POI and DO NOT worry about how the beads line up.
That is my take, please advise and correct me if I am wrong.
JA-
Maybe Rolland can come on and give his take.
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Big Al 29,
You stated the following:
<i>BUT... when I attempted to lower the POI i ended up seeing a totally different sight picture. I now see a ton of space in between the beads so I really don't think the barrel is being bent rather the front of the rib is raising thus creating space between the two beads.</i>
I have a un-single K80 and I just tried your bead space observation and my results were the same when I RAISED the POI. Try this --- loosen your adjustment coin screws and take note of where you are from the zero notch so you can return to it. Turn the adjustment wheel all the way to the stop where there is no gap. Note how the turning resistance increased at the end. You are pulling the barrel up and also bending the rib down. Look at your space between the beads and you will see that it is reduced. Think of two banana's like this ()
Now run the adjustment the opposite way until there is a large gap between, LOWERED POI Check the bead space again and you will see an increase of rib between the beads. The barrel is pushed away from the rib and in fact the rib is being bent (flexed) upward. Again two banana's )(
At both extremes of adjustment look down the barrel and read the reflected rings. The choke ring will appear at the top of the barrel reflection with no gap at the adjustment. The choke ring will appear at the bottom of the barrel reflection with the max open adjustment gap.
I like my un-single adjusted so that there is just a slight amount of take up on the adjustment screw. You will feel a slack or neutral point when doing the above experiment. Mine is set at two notches above the zero notch. Bead space to me is about 1/8th of an inch and like mentioned in a previous post it is a combination of comb height adjustment to achieve POI and also barrel/rib fine tuning.
Jim Warner
You stated the following:
<i>BUT... when I attempted to lower the POI i ended up seeing a totally different sight picture. I now see a ton of space in between the beads so I really don't think the barrel is being bent rather the front of the rib is raising thus creating space between the two beads.</i>
I have a un-single K80 and I just tried your bead space observation and my results were the same when I RAISED the POI. Try this --- loosen your adjustment coin screws and take note of where you are from the zero notch so you can return to it. Turn the adjustment wheel all the way to the stop where there is no gap. Note how the turning resistance increased at the end. You are pulling the barrel up and also bending the rib down. Look at your space between the beads and you will see that it is reduced. Think of two banana's like this ()
Now run the adjustment the opposite way until there is a large gap between, LOWERED POI Check the bead space again and you will see an increase of rib between the beads. The barrel is pushed away from the rib and in fact the rib is being bent (flexed) upward. Again two banana's )(
At both extremes of adjustment look down the barrel and read the reflected rings. The choke ring will appear at the top of the barrel reflection with no gap at the adjustment. The choke ring will appear at the bottom of the barrel reflection with the max open adjustment gap.
I like my un-single adjusted so that there is just a slight amount of take up on the adjustment screw. You will feel a slack or neutral point when doing the above experiment. Mine is set at two notches above the zero notch. Bead space to me is about 1/8th of an inch and like mentioned in a previous post it is a combination of comb height adjustment to achieve POI and also barrel/rib fine tuning.
Jim Warner
A trap gun has both a front sight (BEAD), and a rear sight (YOUR EYE).
Moving either one, independently, changes POI.
Dan Thome: I take it back...if you can't figure this out without asking Vicki Keen for emotional support...then maybe you really _are_ just plain dumb.
Moving either one, independently, changes POI.
Dan Thome: I take it back...if you can't figure this out without asking Vicki Keen for emotional support...then maybe you really _are_ just plain dumb.
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Very good shooters, when they switch from fixed to adjustable ribs, often continue to shoot well though rarely, but occasionally, better.
Poor shooters never shoot better, and many average shooters go right straight down. Dan's surely right on how to go about it, but should have said, for starters, "Set aside a month or two, then..."
But at heart, Buzzgun has laid out the problem correctly. Everything you do, front and back, affects where the shot goes (avoiding the POI/POA hassle.) As others have said, it's a bit of this, they try some of that, than go back . . . And so on, ad infinitum. Fixed ribs you just set your eye where it works and shoot.
Then add the fact that gun makers act as if they can get away with anything when they sell an adjustable-rib gun. All of a sudden, half the problem, making it shoot right vertically, is moved from the factory to the buyer. I've seen "name" guns which _could not_ be made to shoot in any reasonable place.
Ajustable ribs are, for the most part, a solution to a problem few have, and if those that do have a problem know enough to set one up, they could have done it with a fixed rib faster and more securely.
Neil
Poor shooters never shoot better, and many average shooters go right straight down. Dan's surely right on how to go about it, but should have said, for starters, "Set aside a month or two, then..."
But at heart, Buzzgun has laid out the problem correctly. Everything you do, front and back, affects where the shot goes (avoiding the POI/POA hassle.) As others have said, it's a bit of this, they try some of that, than go back . . . And so on, ad infinitum. Fixed ribs you just set your eye where it works and shoot.
Then add the fact that gun makers act as if they can get away with anything when they sell an adjustable-rib gun. All of a sudden, half the problem, making it shoot right vertically, is moved from the factory to the buyer. I've seen "name" guns which _could not_ be made to shoot in any reasonable place.
Ajustable ribs are, for the most part, a solution to a problem few have, and if those that do have a problem know enough to set one up, they could have done it with a fixed rib faster and more securely.
Neil
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410 Posts
Brownnoser?
Another piece that's not been mentioned is the fact that adjustable ribs always move the entire sighting plane, from front to back. Which is another reason a move of the comb is usually necessary. Although with those adjustable ribs where only the front moves it may not be so pronounced and slight changes may work without moving the comb. How many folks out there without an adjustable rib really change the height of the bead on their shotgun? I mean besides those using a Pepsi can.
I would agree that fixed is best. I feel the same way about chokes. But it means that to get things perfect you really need it custom made. Or you simply buy one set up to shoot one of the ambiguous numbers like 70/30 or 90/10. Where a bead stack will put the pattern that much above and below your POA. THEN, your fine tuning comes with comb movement. Or I suppose there are those that may change the height of the front bead, who I don’t know.
For those who just can't put the tools away and are forever changing something. Well you're getting no where fast so stop. I can't imagine it really. I've set up adjustable ribs and PFS's on different guns, and after a few hours at home getting it where I want. Followed by a few rounds at the range with some straights from post 3. I locked them down and never changed them again. Now comes the real work, etching into your brain what it takes to put that pattern on the target every time.
Further, I never shoot on paper. I prefer to lock the trap to throw straights from post 3 and shoot few from there, and the other posts. cls
Another piece that's not been mentioned is the fact that adjustable ribs always move the entire sighting plane, from front to back. Which is another reason a move of the comb is usually necessary. Although with those adjustable ribs where only the front moves it may not be so pronounced and slight changes may work without moving the comb. How many folks out there without an adjustable rib really change the height of the bead on their shotgun? I mean besides those using a Pepsi can.
I would agree that fixed is best. I feel the same way about chokes. But it means that to get things perfect you really need it custom made. Or you simply buy one set up to shoot one of the ambiguous numbers like 70/30 or 90/10. Where a bead stack will put the pattern that much above and below your POA. THEN, your fine tuning comes with comb movement. Or I suppose there are those that may change the height of the front bead, who I don’t know.
For those who just can't put the tools away and are forever changing something. Well you're getting no where fast so stop. I can't imagine it really. I've set up adjustable ribs and PFS's on different guns, and after a few hours at home getting it where I want. Followed by a few rounds at the range with some straights from post 3. I locked them down and never changed them again. Now comes the real work, etching into your brain what it takes to put that pattern on the target every time.
Further, I never shoot on paper. I prefer to lock the trap to throw straights from post 3 and shoot few from there, and the other posts. cls
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CLS, A projectile is a projectile. One BB acts exactly the same as a bullet. The force of gravity pulls them to the earth at the same rate. You have to turn the muzzle up to lob it on to the target. With the comb in a fixed position, A beer can as a front sight (looking across the top of the can) pushes the muzzle down. Your vision dosen't bend thru the middle bead! You see in a straight line, Rear sight(your eye) thru the front sight, to the bird. Some manufactures (not Krieghoff) have done it wrong and have had to change their designs.
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410 Posts
Somebody just shoot me...
cls
cls
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