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 Post subject: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Wed Oct 29, 2003 8:43 pm 
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Numerous times I have read where someone recommends adjusting the height or width of the comb to adjust where the gun is shooting (POI). For example, if the gun shoots low, you are told to raise the comb by adding moleskin or something similar to make it shoot higher. If the gun shoots to the left, you are told to move the comb to the right (cast off).

I happen to disagree with these recommendations even though I've seen them from some supposedly knowledgeable gunfitters. I'll tell you why I disagree.

First, I disagree because we are not shooting a rifle. :!: If this were rifle shooting where we AIM our shots by aligning the front and rear sights, then I would agree. However, this is shotgunning, not rifle shooting. In shotgunning, the idea is to POINT the barrel or rib to the place you want the shot to go in order to intercept the target. This "pointing" is done by visually extending the line of the barrel or rib, not by aiming with the front bead as the front sight and your eye as the rear sight. Once again, this is SHOTGUNNING, not rifle shooting.

Let's take an example of a gun that shoots too high. What do the "experts" tell you to do. Lower the comb, right? Well if your eye is already barely seeing over the top of the receiver, you CAN'T lower the comb or you will be looking into the back of the receiver. :!: Duh.

Let's take another example of a gun that shoots to the right. The "experts" tell us to move the comb to the left (cast on) to correct the problem. Ok, we can do this but that creates a bigger problem. We are no longer using the barrel or rib to visually align our shot. Instead, we are now using the front bead as the front sight and our eye as the rear sight just like in RIFLE shooting. That's the wrong way to do it folks. If you are going to POINT the gun as you would point your finger, you must see the barrel or rib in your peripheral vision and subconsciously extend that line to the target area. BUT, if you do that in this case, you will miss the target because the gun doesn't shoot where the barrel/rib points. It shoots where the front bead and your eye align as in rifle shooting. That's wrong.

OK, I can read your mind. You are now asking, "Well if that is the WRONG way to do it, then what is the RIGHT way to do it." Glad you asked that question. :wink: The RIGHT way to do it is to either adjust the barrel or the rib (if it's wide enough to block your view of the barrel) to the correct POI. This can be done in a variety of ways. One, the barrel can be bent. Or, the rib can be moved or replaced in such a way as to make it align with the POI. Or, non-concentric chokes can be installed to correct for the improper barrel/rib alignment. The final result of this procedure should be that your eye looks directly down the barrel/rib just a fraction of an inch above the centerline of the receiver/rib to the point where the center of the pattern is going to hit. If stock adjustments are necessary to position your eye in this location, then that's fine, but to suggest to someone to change the comb around like you would change the rear sight of a rifle to effect the POI change is simply wrong, in my not so humble opinion. :lol:

BTW, no offense intended toward any stock fitters here. I'm simply exercising my right to disagree with other viewpoints and state my reasons why. 8)


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 12:16 am 
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Ulysses;

Well, you are right about the right to disagree! In my opinion you are all wet!! :P You are correct, this is shotgun shooting, not rifle shooting. With a shotgun YOUR eye IS the rear sight! Where it is in relationship to your visualization and cheek placement on the stock detirmins where the gun will shoot relative to where you are aiming/looking. Sure your way will work, but the adjustable stock is much more efficent, accurate and easialy modified/finetuned to the shooter. If you've been arround many adjustable stocks you will not that when you drop it completly typicaly you can't see what you are shoooting/ correction where the shot pattern is going. That isn't acceptable for any situation I am familiar with. Other than UGLY I see absolutly no problem whatever with an adjustable stock, in fact they are desirable in many situations. You are trying to make a very complex remedy to a very simple problem! Eccentric choke tubes?? For crying out loud! IMHO :roll:

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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 1:10 am 
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Ulysses:

First, your reasoning is relatively sound. Relatively, because a couple of points were overlooked.

First: The eye acts exactly like the rear sight on a rifle.

Second: When a sight picture is created, the three points involved are the eye, the end of the barrel (or the front bead), and the target. Exactly where the barrel is pointing is not that important. The eye sees only the front bead (or end of the barrel) and the target.

Like a rear-sight adjustment on a rifle, the pattern moves in the same direction as the eye (or sight) is moved. That's why combs are raised, to raise the eye and make the gun shoot higher. The shot is not aimed as accurately as a rifle but similiar processes are involved -- eye, bead, target. It is also why doing everything necessary to keep the eye stationary reative to the rib during swings is so important. Basically, it's what stock fitting is all about.

If, for whatever reason, a gun shoots too low and the receiver or action gets in the way when the eye is lowered (by removing wood from the comb let's say,) the gun needs help that does not involve stock fitting. Either the barrel is bent or the fit of the barrel to the action or receiver badly deviates from the design paarmeters.

In such a case, the rib could be removed, the barrel bent up and the rib reinstalled and it might work, at least for a while. The same is true for bending the barrel with the aid of a pickup bumper. Neither is a necessaarily perminant fix.

Lateral movement of the comb to correct a gun's shooting to the right or left works because the eye, the front bead, and the target are aligned to create a sight picture. The fact that the eye is not looking down the center of the rib, simply doesn't matter. It will be apparent to the shooter only when first mounting the gun before calling for a target.

Ribs can be designedfto vary vertical POI but not horizontaal POI. They are not designed to be placed on the barrel at an angle, like the flutes(?) on a wood drill.

Nonconcentric chokes can be used to move the POI in any direction but the amount of movement is limited. An upper limit of 6" comes to mind but I could be wrong. The limit exists because to angle the choke bore any more would deform more shot as it passes through the choke. It would not only be squished by the choke's constriction but would also be compressed against the side of the choke opposite the direction in which the shot was headed as they traveled around the corner. There is also a limit to the amount of metal available to create a nonconcentric choke bore.

Fortunately, it is usually raising of the POI that is desired by the majority of shooters. That is accomplished very easily by raising the comb and is a lot less expensive than installing a tapered rib that is shorter in the front (closer to the barrel)than in the rear.

For the few guns that shoot too low, they are best returned to the factory. The same is true for those that shoot very far right or left on a pattern board.

Lateral movement of the comb should need to be done only to compensate for cast that is not present when it is needed. This is caused by head width, distance between the eyes, and/or shoulder width. Sometimes a more oblique stance will align the eye with the rib if only a little cast is needed. It will at least lessen the amount of cast that is needed if not eliminate the need entirely.

Rollin http://stockfitting.virtualave.net


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 6:41 am 
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In shotgunning you want to adjust the gun so that it will shoot where the eye (rear sight) is looking and not so much concentrate where the barrel bead/rib points. You can remove the front bead for that matter. This can be done by adjusting shooting style if incorrect or adjusting the gun or both. In this manner you are not pointing the shotgun so much as the shotgun is pointing where you are looking.


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 10:01 am 
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AAHHHGGGHHH!! I can't believe I just dropped a bundle on a Citori skeet with an adjustable stock when I could have bought the standard version and just have the rib replaced and the barrels bent! :roll:

Matt


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 10:37 am 
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For what little it's worth,here is my thought's.I agree with Rollin Oswald.Got two shotguns with adjustable comb's.And am able to do what Rollin is talking about.


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 1:51 pm 
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Here's a situation/question with the lateral comb adjustment (cut & pasted from another topic) - see the last paragraph:

I just had a surprising situation with adjustments. I recently picked up a Browning BT-99 Plus with a adjustable comb, recoil unit, and rib. It was set up for a lefty, who said it was "neutral" for him (I'm assuming he meant it shot 50/50 to POA).

The comb was offset to the right and very high. When I first shot it (unchanged from how I received it) I was having to hold 1-2 feet under the bird.

I've now rotated the butt pad to a righty cant, lowered the comb to about 1/2" higher than "flat", and kept the comb where it was horizontally, still offset to the right, but not as much. Gun shoots about 70/30, which is about where I want it. I can shoulder it and weld my cheek into place with minimal head movement, and I get a great site picture.

It strikes me as odd that a lefty would want the comb offset to the right. This would push my face way out of line with the rib. Even stranger is that a lefty shooting buddy of mine shouldered the gun and said, "Huh, this comb is set up just right for me." I guess it just goes to show that everyone is different, and what works for some may not work for others.

-- Sam

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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 2:00 pm 
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I think that some of you are misunderstanding what I'm saying in regards to adjustments to the buttstock. Let me be a little more clear about this matter. Adjustable buttstocks are GREAT. Whether it is an adjustable comb or with shims, I think that they are great. However, the purpose of the adjustable feature is to allow the shooter to get his eye directly behind the centerline of the receiver in line with the barrel/rib, not to adjust his eye for windage and elevation.

Think about it for a minute. If we do as some suggest and adjust the comb to compensate for windage and elevation, we may very well be looking down one side of the receiver and seeing way too much or too little rib. This can create real problems when the shooter is faced with different types of shots in sporting clays. On a fast crosser, the shooter simply POINTS the barrel/rib in front of the target and pulls the trigger. No conscious effort is made to align the eye with the front bead. If your gun is adjusted to shoot where the eye/bead line up, then you may miss that shot because you don't have time to aim. On a long teal shot in which you are going to try to break it at the top of its trajectory, that's one of the few times when you DO aim like a rifle. The trouble is, you are now aiming down the side of the receiver. This can be disconserting to say the least. Can you always remember to aim the same way to one side each time? Not me! I'm going to aim down the centerline of the barrel/rib/receiver. If that's not where my gun shoots, then I'm going to change the barrel or rib, not my EYE.

The gun fitters who say they adjust the POI based on your POINTING of the gun are actually adjusting it based on your AIMING of the gun because pointing has to do with the extension of an imaginary line such as the barrel or rib while aiming has to do with aligning two points (front and rear sight) with the target. I'm not trying to tell anyone else what THEY should do. I'm simply saying that once I've adjusted the buttstock to place my eye directly behind the center of the receiver and slightly over the top of it, if the gun doesn't shoot where my eye aligns with the barrel/rib, then I'm going to do something to the barrel/rib, not jack around on the stock to move my eye. You may do as you wish. :lol:


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 2:28 pm 
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Me, I have a simpler solution, I'd get a different gun, one that does shoot where I'm looking. Actually, I've never seen a shotgun or at least had one that I shot that needed any compensation for windage. Maybe I'm too stupid to know or just lucky enough for it to have never been an issue? Every time I'm either left or right it is because I'm not mounting the shotgun correctly. The guns shoots straight, I'm just not "in it" correctly. That is where the adjustable stock comes into play. But what do I know anyway?? I don't have any adjustable stocks!

BP

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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 2:36 pm 
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Ulysses said
"On a long teal shot in which you are going to try to break it at the top of its trajectory, that's one of the few times when you DO aim like a rifle"

I disagree.... you should ALWAYS have strong focus always on the target )and in some cases on longer shots the "spot" where the target is going to be) but NEVER aim a shotgun unless it is a turkey or slug gun.


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 3:05 pm 
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REM396,

How is it that what you said is any different from what I said? I didn't say NOT to have a strong focus on the target did I? Also, how is a teal at the top of its trajectory any different from a turkey? Both are stationary targets, even if just for a short while. I used the word "aim" to emphasize the need for careful alignment of the sights (whatever they may be) and the target.


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 4:03 pm 
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Ulysses:I finally understand what you mean and that is what I do with my adjustable feature.It lets me get my eye in the correct location.The perfect sight picture every time.Height is correct and centered.


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 4:07 pm 
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Ulysses wrote:
REM396,

I used the word "aim" to emphasize the need for careful alignment of the sights (whatever they may be) and the target.
Ulysses,

Again, the rear sight is the eye and the front site is the bead. The bead is fixed and the eye (the rear site) is aligned based on how the gun is fitted to the shooter.

This is why raising or lowering the comb is a good way to adjust the height of the POI. Obviously lowering the comb can go only so far before the shooter can't see down the rib properly. If one has to go that far, there is something wrong with the barrel(s).

I do agree that adjusting the comb horizontally to fix a POI that is off to the right or left is a bandaid. But it does work okay.

Scott


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 4:22 pm 
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Mako Menace,

Good :!: I'm glad you understand now. Adjustable combs and adjustable stocks are great features because everyone doesn't have the same shape and size of face. Some people have fat cheeks, some have thin cheeks. Some have long necks, some have NO necks. The adjustable stocks and combs make it much easier for a wide variety of people to comfortably get their eye behind the receiver. BUT, once they have their eye properly positioned behind the receiver when they mount the gun, if the gun doesn't shoot where they are looking down the barrel/rib, it's time to change the barrel/rib, NOT to keep changing their face position. That would be like telling a guy whose coat sleeves are too short that if he will only shrug his shoulders a little and draw up his arms slightly then the coat will fit better. :lol: That wouldn't really make the coat fit better. It would simply put him in an uncomfortable position to mask the problem. If the sleeves are too short, the only REAL solution is to lengthen the sleeves, not stand in some awkward position so that the problem is less noticeable. :lol: By the same reasoning, if the gun doesn't shoot where you are looking when your eye is properly positioned behind the receiver, the solution is to correct where the gun is shooting, NOT keep moving your eye.


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 Post subject: Re: Adjusting Comb to Adjust POI. Right or Wrong?
PostPosted: Thu Oct 30, 2003 4:57 pm 
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Ulysses Said
"By the same reasoning, if the gun doesn't shoot where you are looking when your eye is properly positioned behind the receiver, the solution is to correct where the gun is shooting, NOT keep moving your eye."

Now we are on the same page Ulysses. I agree with you on the above. We are just getting confused between terms called point of impact (POI) and point of aim (poa). If the gun is that much off after lining up the eye correctly behind the gun then there is a barrel problem.

Sure, there is no problem raising the comb for trap style patterning and such adjustment is the way to go. I dont think all shotguns are perfect POI but some are just plain dogs and need to be trashed or bent. If they are used, the mods you suggest are much better than trying to make the shooter compensate for it.

In one of your posts you mentioned things like looking down the side of the receiver to get POI correct. There is definately some barrel issues if that is true with a shooter. Sometimes the chokes can be altered by companies like Briley to adjust POI.
As far as my turkey aiming comment.... I was referring to a situation with rifle type sights on a still turkey. My eyes are lining up the front and rear sights with the target. On the teal scenario, if the gun shoots where I look and my mount is solid I only look at the leading edge of that teal that is standing "still". In other words, I would shoot either the top or bottom of that "still" teal and not in any way line up my rib and bead... that is taken care of in a correctly fitted gun and a practiced mount, thus eliminating one more thing that can take my mind off the hard focus on the target. You still have a subconscience knowledge of where the barrel and bead are though and if in a POI barrel problem scenario like you mention can really throw you off.

I always like to shoot a teal on the drop anyway though because most of the larger well set sporting events have many presentations that force you to take them on the drop these days from 60 yards or so.

Many times we are typing our minds on these boards an saying the same things but they come accross as totally opposite.
Break 'em All!!!! :D


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