Tuned barrel

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wsftr
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Re: Tuned barrel

#31 Postby wsftr » Fri Jun 12, 2020 7:56 pm

Trevor Rhodes wrote:OK here is one for the experts. You have a tuner on a barrelled and scoped action in a vee blocked stock, the rifle is as accurate as possible. Now you change to a heavier scope or for this example the vee blocked stock your using is swapped for another vee blocked stock which is lighter. Now will the tuning change with either these alterations.


Yes - its my belief either change will....the stock change I would say absolutely yes. At a minimum you will get a POI change.

But I think you are actually asking - will you see the change in tune in terms of group size or perhaps how well the tune behaves in variable conditions.

Would need more info if thats the case.

ErrolW
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Re: Tuned barrel

#32 Postby ErrolW » Fri Jun 12, 2020 7:58 pm

Some thing I have seen of recent more flex from barrels and action than stock flexing. Long stock versus a short stock what is best ? That's something else to think about. Bipod positioning on the forend. Rear bag and front stands were does it all stop or were does it all begin. So going from an Ali stock the rifle was bucking like a Broncos and uncontrollable to a lite weigh timber stock it has controlled beast .
Last edited by ErrolW on Fri Jun 12, 2020 8:01 pm, edited 1 time in total.

wsftr
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Re: Tuned barrel

#33 Postby wsftr » Fri Jun 12, 2020 7:59 pm

ErrolW wrote:Some thing I have seen of recent more flex from barrels and action than stock flexing. Long stock versus a short stock what is best ? That's something else to think about. Bipod positioning on the forend. Rear bag and front stands were does it all stop or were does it all begin.


with holes in paper :)

bruce moulds
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Re: Tuned barrel

#34 Postby bruce moulds » Sat Jun 13, 2020 9:02 am

pjifl wrote:Maybe it's like this : a stiff stock will tolerate more handling variations in terms of it staying in a more inert state than a flexible stock i.e. the flexible one more easily gets loaded with stored energy. No problems there, until u release the shot. The more inert platform/stock will behave a lot more consistently ?

Again, I cannot see why.

BTW, I appreciate a beautifully made and finished wooden stock and understand why people love them. I was once like that.

But Consider how the Firearms suppliers stay in business by pushing the latest theories - even fads - just as Suppliers to fishermen make a lot of money from the latest lures !


and aint fclass shooters susceptible to this marketing.
often at the expense of basics.
it is a sport where some believe free lunches will beat basic holding and squeezing and will also cheat the wind.
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880
http://youtu.be/YRaRCCZjdTM

wsftr
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Re: Tuned barrel

#35 Postby wsftr » Sat Jun 13, 2020 11:29 am

I do think rigidity is a thing that is needed in a stock - we cant shoot off wet bits of cardboard or a pool noodle but...

Is rigidity the larger factor in a stock design or a necessary derivative due to heavy bullets driving the thinking in terms of long stocks and low CoG?
IMO length is counter intuitive to rigidity - so the design is actually factoring in something of higher value (length) as a primary driver over rigidness.

At the end of the day we say flex is bad but actually currently its a subjective design feature because we don't have a way of quantifying it - or maybe the "squeeze the barrel with the stock" is a way of doing that? But if the stock moves how much movement is considered too much (what exactly is it the manufacturers are arguing about)?

pjifl
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Re: Tuned barrel

#36 Postby pjifl » Sat Jun 13, 2020 1:06 pm

Limitations placed on equipment by overzealous weight restrictions have resulted in a search for extremely light stocks. To retain what was once 'normal' stock rigidity in these very light stocks now necessitates carbon fibre shells and strips. Some call it progress but I am not so sure. Maybe on a lightweight rifle to be carried in the bush but we are more into target shooting.

Shooters have been conned into thinking that limiting rifle weight brings a more even playing field. Actually, the opposite happens. All it does is push the price of competitive equipment up and play into the hands of those who can pay more skilled gunsmiths. Its all a result of demands by shooters who know no better but have the cash to spend hoping this will mitigate against poorer technique.

Carbon fibre is a marvelous material. But it has its limitations when design is taken to extremes. Like when a Yacht's keel falls off.
It is good to see it used well but I don't think design rules should make it almost mandatory so as to comply with weight rules.

it is better if the Centre of Mass of the rifle as a unit is not too low and this should be considered in a stock.

I think stiffness has become an end in itself. Like, why is it better ! Vehicles do not benefit from extra stiff uncompliant suspension. A TR shooters glove contact is not meant to be rigid - rather it is compliant.

wsftr
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Re: Tuned barrel

#37 Postby wsftr » Sat Jun 13, 2020 1:24 pm

pjifl wrote:Limitations placed on equipment by overzealous weight restrictions have resulted in a search for extremely light stocks. To retain what was once 'normal' stock rigidity in these very light stocks now necessitates carbon fibre shells and strips. Some call it progress but I am not so sure. Maybe on a lightweight rifle to be carried in the bush but we are more into target shooting.

Shooters have been conned into thinking that limiting rifle weight brings a more even playing field. Actually, the opposite happens. All it does is push the price of competitive equipment up and play into the hands of those who can pay more skilled gunsmiths. Its all a result of demands by shooters who know no better but have the cash to spend hoping this will mitigate against poorer technique.

Carbon fibre is a marvelous material. But it has its limitations when design is taken to extremes. Like when a Yacht's keel falls off.
It is good to see it used well but I don't think design rules should make it almost mandatory so as to comply with weight rules.

it is better if the Centre of Mass of the rifle as a unit is not too low and this should be considered in a stock.

I think stiffness has become an end in itself. Like, why is it better ! Vehicles do not benefit from extra stiff uncompliant suspension. A TR shooters glove contact is not meant to be rigid - rather it is compliant.


Yip - thats where I have landed.
My racing days taught me too much flex is a bad thing - but so was too much rigidity. A really rigid bike frame loaded up tyres and suspension. Tyres squirmed and so the sidewalls got lowered and became more rigid - the suspension needed to absorb the outcome of the rigidity - no free lunch - the package needed to work.

Our rear bags and front rests are like the suspension in my opinion (hint read any articles about making the front bag too hard)...something worth thinking about for those purchasing the ultimate in rigid stocks.

I believe the materials are driven by external ballistics - we need to shoot heavier bullets is the primary starting point for advantage.

bruce moulds
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Re: Tuned barrel

#38 Postby bruce moulds » Sat Jun 13, 2020 1:34 pm

pete,
you are making good points here.
all things in balance.
take here means you have to give there.
and whatever, the bottom line is technique.
again, no free lunches, as even the best equipment will not negate poor technique.
there exist people who think the whole thing is ruled by a formula, and they know the equation.
trouble is, over the years you see the equation change due to current theory.
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880

http://youtu.be/YRaRCCZjdTM

Gyro
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Location: New Zealand

Re: Tuned barrel

#39 Postby Gyro » Sun Jun 14, 2020 1:05 pm

Here's some more really basic physics that relates to the above banter : with all things equal ( yes I know that's relative ) why might a gun that's heavier have an advantage ? Here's a clue : heavier means a greater inertia value which means the object has a greater resistance to movement. I wonder if a stiffer stock might also have a greater resistance to movement in terms of it not only having a greater resistance to storing flexural stresses in the 1st place ( which release/alter during recoil ) as well as resisting bending during recoil, with both behaviours I presume aiding in repeatability ?

Lord knows there's some complicated theory about but unless I'm mistaken ( again ) a great deal of what we comp shooters are dealing with is not complicated ?

Like why a race bike frame is better stiffer, along with the tyres being stiffer. Like why big race yachts run steel cables instead of rope where they can ... Simple stuff ?

wsftr
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Re: Tuned barrel

#40 Postby wsftr » Mon Jun 15, 2020 9:03 am

I think its more a question of how rigid is rigid and what absorbs those vibrations - the racing example puts a huge amount on the suspension - making everything rigid would be very bad and unusable.
A Barnard P is probably more rigid than a Panda F-class but there is an interesting concept around the material used in the Panda F-class with respect to dampening qualities.
Last edited by wsftr on Mon Jun 15, 2020 9:12 am, edited 1 time in total.

Rich4
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Re: Tuned barrel

#41 Postby Rich4 » Mon Jun 15, 2020 9:11 am

The racing analogy is very astute I think, stiffness exposes weakness in other areas rather than being a detriment, thus the tyres-frame have focused efforts on the suspension allowing movement to be controlled, so if it’s going to move I want to control it, really heavy guns are reported to not shoot any better in heavy bench rest (reportedly IDK)

pjifl
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Re: Tuned barrel

#42 Postby pjifl » Mon Jun 15, 2020 9:41 am

Has anyone any experience with V blocks compliantly rubber coupled to the main block in a stock or something similar. This was a trend at one time but it seems to me that there are other systems that shoot just as well ? Some were in effect a linear rubber controlled mini recuperator.

I remember the first time I shot a synthetic stock. It was more or less hollow and vibrated to the ear. At the time I considered it inferior to a wooden stock - but it shot well despite the annoying 'Boing' after each shot.

Peter Smith.

Gyro
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Re: Tuned barrel

#43 Postby Gyro » Mon Jun 15, 2020 11:12 am

I shall scribble more after work but Stuart Otteson wrote a few really cool and beautifully written books about rifle actions, analysing them from a mechanical engineers viewpoint. In one small volume he analyses a few target actions and triggers. Bloody interesting. Perhaps dated now because there are many top level target actions around now but the principles have not changed. Yes Peter done the rubber thing. BTW the original Stolle Panda is 7075 T651 Ally and that's another story .... all cool stuff.

pjifl
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Re: Tuned barrel

#44 Postby pjifl » Mon Jun 15, 2020 2:06 pm

Has Otteson produced an updated book on recent target actions or is it simply a recompilation of his older Book 1 and Book 2 ?

For anyone interested, I can confirm that these older books are outstanding for what they are. He often goes into detail forgotten by many today. These old books are highly sought after and I am lucky that I have both.

Most emphasis is on some of the best older actions. It would be nice if he produced a Book 3 on modern developments over the last 10 years.

Gyro
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Re: Tuned barrel

#45 Postby Gyro » Mon Jun 15, 2020 4:22 pm

“Benchrest Actions and Triggers” was 1st printed in 1983 and Otteson discusses/dissects seven BR actions and four BR triggers. In the 1st chapter he writes … “The importance of rigidity or stiffness in an action, particularly one used for benchrest competition, is widely recognised in the abstract. That a rigid receiver contributes to rifle accuracy is in fact almost manifestly obvious. But how much stiffness is necessary and where we encounter a point of diminishing returns are extremely difficult questions”.

The full length rubber strips along a v-block mounted octagonal receiver was done here in NZ with the H&H/Millennium action. I think it was called the “flexi-bed system” and I remember talking to John Hastie ( one half of the H&H team, the other Tony Halberg ) and he said in it’s day it was a revelation ! For TR shooters. Perhaps it was. So did it work ? Yes. Does it still work for some ? Yes. BUT it breaks down and needs user-knowledge to monitor and perform upkeep. And can u successfully hang a heavy barrel off this system ? As far as I’m aware, NO. Hence using Ottesons analogy : at some point, subjecting that system to a heavier barrels weight will introduce diminishing returns. Sound familiar ?


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