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Discussion Starter · #1 ·
Yes I have heard all about the crap Factor comb adjusters on Bt 99 -- My Question is why does a gun maker make a Adjustable comb stock That starts out at 80/20 POI -- My golden clay is exactly that! do people ever adjust it up from there? my question is --Up dating to a upward pin system I still need to remove wood ? Since the factory pins go down into the stock, can I remove the comb plates --rerouter 1/4 inch deeper for the comb plate and sand down the comb to lower the POI - giving me a 60/40 starting point? and a cheaper fix?
 

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Lots of trapshooters like a POI at 100% or higher. My BT from Guns Unlimited shoots 80/20 with the comb all the way down. I like being able to float the bird above the barrel.
 

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Since the factory pins go down into the stock, can I remove the comb plates --rerouter 1/4 inch deeper for the comb plate and sand down the comb to lower the POI - giving me a 60/40 starting point? and a cheaper fix?
As long as you're seeing at least 1/4" between the beads. Otherwise you are going to be staring at the operating lever and back of the receiver.
 

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As long as you're seeing at least 1/4" between the beads. Otherwise you are going to be staring at the operating lever and back of the receiver.
This is a good point. If the rib is high enough at the rear, even looking flat down the rib could result in a POI higher than desired.
 

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Discussion Starter · #5 ·
Shot a ljutic - figure eight , 70/30, or 9 inches high at 39 yards with a 1/8 comb spacer -Browning barrel looks like a landing strip between the beads --meaning I must be looking down on the barrel -If my memory serves me right - Rolin Oswald's Stock fitters Bible calulation on a 34" barrel you will get three inches POI change per 1/8 comb adjustment -I should gain the 1/8" I need and them some-Lot cheaper than rib work and I still will have all my comb adjustment up.?
 

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What is the difference in drop at comb b/w the Browning and Ljutic? That would explain your difference in sight pictures.

The rib angle as well as it's relationship to the comb are what dictate POI. Adjusting the comb won't do anything to the rib angle, so it's quite possible you'll see a figure 8 and the POI will still be higher than what you want.
 

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Discussion Starter · #7 ·
The rib angle as well as it's relationship to the comb are what dictate POI. Adjusting the comb won't do anything to the rib angle,
You hit the nail on the head --Rib angle dictates my Barrels POI -- and Browning does not have a parallel rib to this barrel --But when you do not see a figure 8 indicates to me that I am looking DOWN on the barrel ?-But adjusting the comb down until I can stack the beads will get me the lowest POI For is gun - which I can't due now. - In my mind means I need to remove wood? - And you have me scratching my head on the drop at the comb - because both barrels have a different rib to barrel angle? determining sight picture or POI ?-- Time to dig out Rollins Oswald's book again
 

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RRisumshake:

Forgive me for saying so -- it's difficult to tell for sure with what you've written so far -- but you might have a rather shaky understanding of a couple of basic shotgun design concepts.

My Question is why does a gun maker make a Adjustable comb stock That starts out at 80/20 POI -- My golden clay is exactly that!
Browning barrel looks like a landing strip between the beads --meaning I must be looking down on the barrel
Just to be clear, in the case of your BT-99 Golden Clays, Browning didn't really "make an adjustable comb stock that starts out at 80/20 POI". They manufactured this gun (just like any manufacturer does with each gun model) with a specifically-designed and purposely-chosen Drop at Comb dimension . . . when the adjustable comb is at its lowest position, Drop at Comb on this BT-99 variant is 1 - 9/16" according to Browning's listed specifications. The fact that this Drop dimension on this gun places your eye a significant distance above the rib's surface doesn't mean it will do so for all other shooters. For other shooters with this same BT-99 model, when the comb is in its lowest position, their eye may be higher or lower than yours, with the corresponding different POIs those shooters would get. Other shooters with this same gun and same comb position can indeed have a rather low eye position and therefore a POI lower than what you get with your higher eye position. So, claiming that Browning designed this gun's adjustable stock to "start out at 80/20" is not a true statement. I don't know why you apparently think otherwise, since you yourself said the following (a basically correct statement, by the way) in a post this past November:

[From a November 2019 post]: I have to laugh at people saying its a 70/30 or 90/10 gun everything depend on the person shooting it -- build -mount-and eye position.

Additionally . . .


. . . adjusting the comb down until I can stack the beads will get me the lowest POI For [this] gun
That's true of any shotgun with a fixed rib . . . well OK, with any gun, you could position your eye even a little lower than stacked beads (i.e., a dead flat eye alignment low along the rib's surface), and thus lower the POI a slight bit more, but the important concept is that on any fixed-rib gun, the slope of the rib the manufacturer designs into the gun dictates the lowest-possible POI achievable with that gun. If a gun has a fixed rib with a lot of down slope, it will be near impossible for any shooter to obtain a really flat POI with such a gun . . . but of course, that's the whole idea of designing a (Trap) gun that way.

Also, you originally sort of hinted that your current eye position is 1/4-inch "too high", and you seem to think that such an eye height definitely equates to an 80/20 POI with this gun. Maybe, maybe not . . . did you actually test it? Furthermore, there's no guarantee that lowering the comb 1/4-inch (is that the amount required to stack the beads for you with this gun?) will automatically produce a 60/40 POI with this gun either, which seems to be the "starting POI" you want. True, many shooters report that a BT-99 with its standard-sloped rib (like your Golden Clays) does produce a rather flat-ish POI with beads stacked, but 60/40 is only "probable" in this case . . . not a guarantee for every shooter.

. . . and Browning does not have a parallel rib to this barrel
Well . . . that's because it's a Trap gun, intentionally designed with Trap gun characteristics.

But when you do not see a figure 8 indicates to me that I am looking DOWN on the barrel ?
Why phrase that as a question? It's immediately obvious to you that this is the case, correct? You say the stock on this gun (even with the adjustable comb in its lowest position) places your eye some distance above the rib that's higher than stacked bead alignment. So yes, you could call this "looking down on the barrel" . . . the end result of course is that your Line of Sight is angled more steeply downward (steeper than the rib's built-in slope), and that is what will cause your POI to be higher than if your eye was positioned lower.

In my mind means I need to remove wood?
When the comb is at its lowest position on this fixed-rib gun, if your eye is truly too high above the rib ("too high" is defined as the resulting POI really does prove too high for your liking and/or you simply don't like how much rib you're seeing), then yes, you must lower the comb somehow. As you mentioned, the only other alternative is to install an add-on rib with whatever height and slope meet your desired "bead gap" and "starting POI" preferences.
 

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I'm new to the shotgun fitting thing, and trying to get an understanding. I originally thought the simple fix on comb height was an adjustable butt plate, but then realized that changes the angle or front and rear height of the comb. With rifle stocks, I've always had the understanding and practiced, having the front of the comb at the same height or preferrably lower than the rear of comb, so when the rifle recoils back, the comb is not climbing into your cheek. If I raise the recoil pad, so I drop actual stock height, I am getting the check lower and seeing less rib, but also raising the front height of comb, relative to rear.

Does that make sense, and am I seeing a problem being caused, or am I wrong or missing something?
 

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I'm new to the shotgun fitting thing, and trying to get an understanding. I originally thought the simple fix on comb height was an adjustable butt plate, but then realized that changes the angle or front and rear height of the comb. With rifle stocks, I've always had the understanding and practiced, having the front of the comb at the same height or preferrably lower than the rear of comb, so when the rifle recoils back, the comb is not climbing into your cheek. If I raise the recoil pad, so I drop actual stock height, I am getting the check lower and seeing less rib, but also raising the front height of comb, relative to rear.

Does that make sense, and am I seeing a problem being caused, or am I wrong or missing something?
If you fix your head to the comb, raising and lowering the butt plate only changes the angle of your head. While this does have some impact on sight picture and POA/POI, the much bigger factor is to change the height of the comb relative to the bore. In general, I adjust LOP first, comb height and cast second and pad drop third. There's cant and pitch as well but I like to get shooters close before tweaking these and I'm looking for a person's head to be mostly forward and lowered (not tipped) onto the comb. Tipping is a sure way to get a nice knot on the cheek bone.

-Scot
 

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Thanks Scot. I think that makes sense. I understand the progression of LOP first, then comb height and cast. I thought you used the adjustable butt to change height of comb if you did not have adjustable comb stock. If you have the comb adjusted to the correct height, what are you adjusting for when you change pad drop and wouldn't that change the comb height.

Sorry to be so dense, and thanks for info.
 

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Hi Gunner621:

I thought you used the adjustable butt to change height of comb if you did not have adjustable comb stock. If you have the comb adjusted to the correct height, what are you adjusting for when you change pad drop and wouldn't that change the comb height.
Not really correct. An adjustable recoil pad's vertical movement changes the stock dimension called "Drop at Heel". And in fact, moving an adjustable recoil pad changes the Drop at Heel dimension independently of the comb's other Drop dimensions (Drop at Comb, Drop at Face). Being able to independently alter Drop at Heel without affecting Drop at Comb/Drop at Face is the main reason adjustable recoil pads exist.

When you say "change the height of the comb", you must ask yourself, "comb height relative to what"? I think that's the part of the puzzle you're not aware of yet. If you haven't done so already, please study how the various comb Drop dimensions are defined, what datum line they're referenced from, and how/why shooters alter them for improved stock fit and Point of Impact tweaking.

Best regards,

Jeff
 

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I understand the drop dimensions and what they are relative to, guess I mispoke. It seems that if you change the drop at the heel, with an adjustable pad, you are changing the relative placment of cheek on comb, but maybe I am still missing something. I am hoping there is someone here that actually works with shooters, actually doing these stock adjustments, especially with youth, that could help me understand how this works. Specifically, I am still not understanding, why, if you have adjusted the comb, so your point of aim is where desired, that you would change the butt plate positions, or maybe be accurately stated, what your are gaining or trying to gain by doing this.

Thanks to anyone who can help,

Bill
 

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Hi Gunner:

A very quick summary . . .

Specifically, I am still not understanding, why, if you have adjusted the comb, so your point of aim is where desired . . . .
There's the dilemma. If all you've adjusted so far is the comb (or if that's the only adjustable device on your gun) . . . yeah, sure the comb might be positioned perfectly to give you the desired point of aim (as you call it), but that certainly doesn't mean that overall stock fit is OK. It might be, it might not. "Stock fit" is much more than simply optimizing Point of Aim and Point of Impact. Example: if the stock length is so long that you can't even shoulder the gun properly, it's irrelevant that the comb might be positioned perfectly, agreed?

It seems that if you change the drop at the heel, with an adjustable pad, you are changing the relative placment of cheek on comb, but maybe I am still missing something. I am hoping there is someone here that actually works with shooters, actually doing these stock adjustments, especially with youth, that could help me understand how this works. Specifically, I am still not understanding, why, if you have adjusted the comb, so your point of aim is where desired, that you would change the butt plate positions, or maybe be accurately stated, what your are gaining or trying to gain by doing this.
Which is typically done first?

1. Adjustable recoil pad is for optimizing Drop at Heel. As Scot mentioned in his post above, stockfitters typically work "back to front" when altering a shooter's stock fit. So, at the rear of the gun, the stockfitter will first get overall LOP, Drop at Heel, pitch, and toe-out optimized for a shooter. Why is Drop at Heel tweaked? In my experience, I advise that Drop at Heel (along with stock pitch) be set to ensure that the recoil pad's full surface area makes full contact with the shooter's shoulder pocket. For a given shooter, the optimum Drop at Heel is most affected by the shooter's physical attributes such as neck length / shoulder slope. With insufficient Drop at Heel, shooters with long necks or sloping shoulders often need to "scrunch up" or "shrug" their shoulder a ridiculous amount upward to get their shoulder pocket up to the recoil pad . . . this can ruin smooth gun handling, and is a classic case of a shooter fitting himself to the gun versus fitting the stock to the shooter. Such shooters often have half the recoil pad above their shoulder, touching nothing but air. OK if you want to shoot that way, but not really recommended. An adjustable recoil pad is a super-convenient way to optimize the Drop at Heel stock dimension.

2. Next, keeping the Drop at Heel as already optimized, the stockfitter would adjust the comb horizontally and vertically to get the shooter's eye aligned horizontally with the rib centerline, and at whatever height above the rib's surface gives the shooter the Point of Impact (POI) he wants with this gun. Of course, here we have to work with the shooter's facial structure, his preferred technique ("head upright" style . . . or an incurable stock crawler . . . and everything in between).

3. At this point in the stockfitting effort, some fine-tuning is often still required, typically discovered when firing the gun on clay targets, such as a little too much recoil to the face or shoulder. So, you might make some small additional adjustments to the comb, Drop at Heel, or pitch, etc. But, stop worrying what effect moving an adjustable recoil pad a 1/4-inch up or down will have on POI at this point . . . likely negligible in the shotgun world. Sure, changing Drop at Heel might cause you to place you face on the comb a little different than you did before (not guaranteed to do so), but that new face position might be just what you need for good overall fit, especially how the comb meshes with the cheekbone structure. If not, move the adjustable comb to re-obtain good comb fit and desired POI again. If the comb's adjustment capability is insufficient, sanding/re-shaping of the comb cross-section is often the solution.

4. Of course, throughout the entire process, the stockfitter must work with the shooter's physical form, experience level, good/bad habits and willingness to alter his technique if advisable. Not every fault should be solved by stock changes.
 

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Jeff,

That explanation makes sense to me. (I should clarify and apologise that I used the term point of aim. I meant to say point of impact. Not sure if it is old rifle shooting mindset creeping in, or just old age, but I understand that the whole exercise in getting the stock to fit is not aiming the shotgun at all, which is why I am trying to understand things as well as I can.)

Thanks again,

Bill
 

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Hi Gunner:

A very quick summary . . .



There's the dilemma. If all you've adjusted so far is the comb (or if that's the only adjustable device on your gun) . . . yeah, sure the comb might be positioned perfectly to give you the desired point of aim (as you call it), but that certainly doesn't mean that overall stock fit is OK. It might be, it might not. "Stock fit" is much more than simply optimizing Point of Aim and Point of Impact. Example: if the stock length is so long that you can't even shoulder the gun properly, it's irrelevant that the comb might be positioned perfectly, agreed?



Which is typically done first?

1. Adjustable recoil pad is for optimizing Drop at Heel. As Scot mentioned in his post above, stockfitters typically work "back to front" when altering a shooter's stock fit. So, at the rear of the gun, the stockfitter will first get overall LOP, Drop at Heel, pitch, and toe-out optimized for a shooter. Why is Drop at Heel tweaked? In my experience, I advise that Drop at Heel (along with stock pitch) be set to ensure that the recoil pad's full surface area makes full contact with the shooter's shoulder pocket. For a given shooter, the optimum Drop at Heel is most affected by the shooter's physical attributes such as neck length / shoulder slope. With insufficient Drop at Heel, shooters with long necks or sloping shoulders often need to "scrunch up" or "shrug" their shoulder a ridiculous amount upward to get their shoulder pocket up to the recoil pad . . . this can ruin smooth gun handling, and is a classic case of a shooter fitting himself to the gun versus fitting the stock to the shooter. Such shooters often have half the recoil pad above their shoulder, touching nothing but air. OK if you want to shoot that way, but not really recommended. An adjustable recoil pad is a super-convenient way to optimize the Drop at Heel stock dimension.

2. Next, keeping the Drop at Heel as already optimized, the stockfitter would adjust the comb horizontally and vertically to get the shooter's eye aligned horizontally with the rib centerline, and at whatever height above the rib's surface gives the shooter the Point of Impact (POI) he wants with this gun. Of course, here we have to work with the shooter's facial structure, his preferred technique ("head upright" style . . . or an incurable stock crawler . . . and everything in between).

3. At this point in the stockfitting effort, some fine-tuning is often still required, typically discovered when firing the gun on clay targets, such as a little too much recoil to the face or shoulder. So, you might make some small additional adjustments to the comb, Drop at Heel, or pitch, etc. But, stop worrying what effect moving an adjustable recoil pad a 1/4-inch up or down will have on POI at this point . . . likely negligible in the shotgun world. Sure, changing Drop at Heel might cause you to place you face on the comb a little different than you did before (not guaranteed to do so), but that new face position might be just what you need for good overall fit, especially how the comb meshes with the cheekbone structure. If not, move the adjustable comb to re-obtain good comb fit and desired POI again. If the comb's adjustment capability is insufficient, sanding/re-shaping of the comb cross-section is often the solution.

4. Of course, throughout the entire process, the stockfitter must work with the shooter's physical form, experience level, good/bad habits and willingness to alter his technique if advisable. Not every fault should be solved by stock changes.
Not every fault should be solved by stock changes.

Truer words were never spoken.

-Scot
 

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I recently purchased a new Bt99 Plus. The only thing adjustable is the comb. Shot it the first evening with no adjustments. Went home raised the comb the thickness of a pop sickle stick, moved the comb as far right as I could. I'm a right handed shooter, 5'8" no neck. This adjustment floats the bird a bit more than my old BT, and I love it. this is one easily mounted Trap gun I have ever owned. No head bobbing or twisting. How much do I float the bird? Hell, I don't know, it looks like a foot. All I know is that it is easier to keep my head on the stock, and it powders the birds. I don't even think about it. Just concentrate on the bird. Hey Steve how are you doing?
 

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Yes I have heard all about the crap Factor comb adjusters on Bt 99 -- My Question is why does a gun maker make a Adjustable comb stock That starts out at 80/20 POI -- My golden clay is exactly that! do people ever adjust it up from there? my question is --Up dating to a upward pin system I still need to remove wood ? Since the factory pins go down into the stock, can I remove the comb plates --rerouter 1/4 inch deeper for the comb plate and sand down the comb to lower the POI - giving me a 60/40 starting point? and a cheaper fix?
You can modify the stock to fit your needs, be careful not to run into the stock bolt hole.
 
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