Guns with POI adjustments

[Dog Tyred]

It's simple trigonometry. If you keep the bead in the same place (relative to the target) but raise your eye level above the centre line of the barrel, the gun will shoot higher. The higher you raise your eye the higher the POI will be. However, what will also happen is you will see more rib (the height between the rear and front of the barrel). An adjustable rib allows you to alter the hieght of the POI while maintaining the same rib picture. And this is nothing to do with barrel watching.

example: while watching my lad shooting trap recently I noticed he was hitting a lot of targets on the bottom edge, so was likely to be shooting underneath them. Unknown to him I raised his comb a fraction ( not a huge amount but enough to make a difference) and next shoot his was smacking them right in the middle and shot 192 ex 200. No other changes other than raising the comb. 

I rest my case

DT

 

[Hamster]

What total rot  

I can only reiterate - I thank any and all deities associated with shooting that I never had some of you coaching me.  And there is no smiley since that is dead serious

I agree completely with DT.  I also agree that that the adjustos seem too fragile for me to venture there even if I thot there was a need.

Ian - you need to observe the comma in Greg's post and understand what he really intended.  Just sayin'

What level do you shoot Sporting clays at if I may ask ? You have to make allowance for the fact we're talking within that particular context and not primarily shooting going aways as in American trap. 

There are plenty of high calibre shooting people on record as saying the exact same thing I am saying not to mention Alan Rhone's article !!!

Clamp the gun in a vice and shoot it with and without a comb, report back if the POI alters. 

 

[Wonko the Sane]

I'm really not going to get involved with this.  It makes no difference what game(s) you shoot.  A shotgun is a shotgun and just like any tool it functions best tailored to its use.  Think and do as you like if it works for you.   :thumbsu:  

I've read any number of "authorities" who wrote total bollocks and Rhone certainly qualifies.  If you need a Limey authority try Yardley.  He certainly tells the truth.

 

[Hamster]

I'm really not going to get involved with this.  It makes no difference what game(s) you shoot.  A shotgun is a shotgun and just like any tool it functions best tailored to its use.  Think and do as you like if it works for you.   :thumbsu:  

I've read any number of "authorities" who wrote total bollocks and Rhone certainly qualifies.  If you need a Limey authority try Yardley.  He certainly tells the truth.

I read plenty of books when younger but it slowly dawned on me that not everything one reads is gospel so I now exclusively try and find the truth through experience at least where possible. 

 

[chippy]

it seems like some on here are confusing POI of the gun with POI of the shooter and gun. 

 

[AW13]

it seems like some on here are confusing POI of the gun with POI of the shooter and gun. 

This whole thread is becoming very convoluted. 

Think my head is beginning to hurt now. 

 

[Gavin]

This is entertaining but I can see both sides and there is truth in what hamster is saying. Trap shooters well any I know shoot off the end of the gun and shooting in such a way comb hight will have a huge impact on where the gun shoots. On a pattern plate locked in like a trap shooter an the bead on the mark a raised comb will shoot higher no body disagrees with that

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[Mutley]

When you raise the comb, it doesnt lift your neck and head or eye height, it stays the same.

So your eye to target stays on the same line, the raising of the comb pushes the stock away from your face, so that alters the angle of barrel to target, this will raise the nose of the gun which in turn makes it shoot higher.

If you adjust a rib on the other hand or barrel hanger (K80), or even the sliding wedge ( ST 80 ST100)or twiddly wheel (ST150 and Carrega Manufrance) the sight picture stays the same, but alters the POI without changing what you see.

I had a customer with an MX10, we set the sight picture so he was happy, then we jacke the rib fully up at front and down at rear when he shot sporting, then opposite for DTL and ABT.

If you have a parallel comb that will push the gun down paralell and not alter poi as much as a traditional stock, just make it a pain in the arse to shoot.

 

[paul b]

Just to add a little more to this .

What happens if you raise the comb but not level ie the back of the comb is higher than the front.

 

[DavidJ]

Clamp the gun in a vice and shoot it with and without a comb, report back if the POI alters. 

But no one ever shoots a gun clamped at the action, it's clamped against your cheek bone or there abouts.

 

[Mutley]

Just to add a little more to this .

What happens if you raise the comb but not level ie the back of the comb is higher than the front.

Top lever splits the end of your nose...... .

In reality it still alters poi, but it locks you from sliding the head back, Rivetta makes a lot of stocks like this, I had one on an ASE Beretta, very strange to shoot until you got used to it, it made me lift my head at first because it felt different. Ive just done one for a customer, it just works for him better than anything.

Am playing with something that Claudio at A1 talks about, the best stock for trap he says is a high game stock, as a stock with a lot of front to back drop keeps your head up and more vertical, so you are not lifting your eyes, so your vision is better, I have made one for a Browning, it is 31 - 60, looks starnge, but it allows you to mount the gun high in the shoulder but it keeps the head up. Works very well, up to now...

 

[ips]

When you raise the comb, it doesnt lift your neck and head or eye height, it stays the same.

So your eye to target stays on the same line, the raising of the comb pushes the stock away from your face, so that alters the angle of barrel to target, this will raise the nose of the gun which in turn makes it shoot higher.

If you adjust a rib on the other hand or barrel hanger (K80), or even the sliding wedge ( ST 80 ST100)or twiddly wheel (ST150 and Carrega Manufrance) the sight picture stays the same, but alters the POI without changing what you see.

I had a customer with an MX10, we set the sight picture so he was happy, then we jacke the rib fully up at front and down at rear when he shot sporting, then opposite for DTL and ABT.

If you have a parallel comb that will push the gun down paralell and not alter poi as much as a traditional stock, just make it a pain in the arse to shoot.

exactly ?

But no one ever shoots a gun clamped at the action, it's clamped against your cheek bone or there abouts.

exactly ?

 

[Garwood]

So would a deeper forend raise the poi ?

 

[ips]

it seems like some on here are confusing POI of the gun with POI of the shooter and gun. 

um, its simple really poi is exactly that and poa is exactly that. I have no idea how the two can be confused or why we are even debating it. It is what it is, end of...

 

[westley]

many of us remember the days of fixed choke, fixed comb even adj trigger lop was a rarity. Oh the good old days of unslip your gun and shoot the dammed thing.

Now it is adjustable and interchangeable and completely variable, you wear it around your neck and hit everyone else with it  !

 

[Hamster]

When you raise the comb, it doesnt lift your neck and head or eye height, it stays the same.

It doesn't physically lift your neck/head/eye but the effect is very much to lift your neck/head/eye above the line of the rib, hard to even begin to argue otherwise !!

But no one ever shoots a gun clamped at the action, it's clamped against your cheek bone or there abouts.

Exactly, that's why what happens in actuality differs to what the numbers say. 

The reason I use the analogy of clamping the gun is to simplify and break down why the comb in and of itself CANNOT raise the poi but a barrel hanger WILL raise the point of impact whether the gun is held in a vice or not because the former is perceived the latter is factual. 

 

[Hamster]

For those having trouble with solid clamps I have devised a new test using goose feathers  :clover: , insert laser beam pattern thingy into either barrel, loosen comb screws so comb sits on lowest setting, gently lay gun on bed of feathers and then :

take hold of comb and begin lifting whilst observing POI beam, if the beam raises as you remove the comb then call Nasa immediately and inform them you're on the way to perfecting teleportation. 

Raising the comb does not raise point of impact, what is actually happening is that YOUR point of aim is being lowered, in other words perception is being altered.

Barrel hangers are different because they physically alter POI whilst the view along the rib remains the same. 

 

[Salopian]

Whilst we are muddying the waters !

If I shoot at a target and hit it , if I raise my point of aim  ( POA) and miss it , will I have altered my point of impact (POI) ?

What happens if I shorten my barrels from say 32" to 25" if the barrels were set correctly at 32" ?

What happens to your shot pattern with a Longthorne manufacturer gun where the barrels are bored parallel to each other , where is the convergance point and point of impact compared to point of aim?

What happens with a Krieghoff where the barrel hanger adjustment has little to no effect upon the top barrel?

 

[Hamster]

Whilst we are muddying the waters !

If I shoot at a target and hit it , if I raise my point of aim  ( POA) and miss it , will I have altered my point of impact (POI) ?

What happens if I shorten my barrels from say 32" to 25" if the barrels were set correctly at 32" ?

What happens to your shot pattern with a Longthorne manufacturer gun where the barrels are bored parallel to each other , where is the convergance point and point of impact compared to point of aim?

What happens with a Krieghoff where the barrel hanger adjustment has little to no effect upon the top barrel?

Valid question and the answer is nothing, only the barrel which has the capacity to have its POI altered via a hanger can do so, the other has to yield to the same set of realities as an ordinary shot gun.

Regarding barrel convergence again valid point but a huge part of the reason why minor alterations in POI & POA can be done without having to make conscious allowances whilst actually shooting is that shotguns are (scatter guns) which as we all know spread their load in give or take 25-30".

 

[Salopian]

So ! If my Krieghoff is shooting high , I lower the comb height and it then shoots lower .

Have I altered the point of aim and / or the point of impact?