AusVarmint

Tony Z wrote: ↑Wed Mar 14, 2018 8:10 pm Rail guns have been steel or alloy construction for decades and are without doubt the most accurate rifles on the planet. Universal receivers used for decades are blocks of steel bolted to steel or concrete slabs with a barrel screwed in and are used by all bullet manufacturers for QA in test tunnels. Charles Bailey shot unheard of groups at 1K 20 years ago in the "USS Enterprise" all steel and alloy 120 pound gun right up until they changed the rules to prevent him competing.
I believe Jackos recent stocks have utilised the alloy ribs we have used since the early 2000s Alan. I would say Jacko is using very rigid stocks and has done so for some time. The question of rigidity is rather obvious with the above examples. As for resonance, carbon fibre and kevlar are about as bad, or good, as it gets if you are refering to transference. Personally i think resonance only plays a part when it's inconsistent. Same goes for flex.
It is not what it's bolt to, it's what it's bolted to does before the bullet leaves the barrel. Weight restrictions mean compromise. That compromise results in flex and it is that flex that determines the way the barrel and action and even the stock in combination flex. If you recall our discussion the other night i mentioned the guy who bolted his Stolle to a fence picket to prove that stock resonance and design was horse shit. Well yes he won a match and proved that a 50 cent pine board can perform as good as a thousand dollar piece of glue and balsa. But he is both wrong and right. If you recall i had two stocks for the Diamondcrap. The SGY and the MBR. The 30 inch barrel in the SGY stock had vertical that could not be cured. The MBR was longer, stiffer and had more rear bias resulting in better balance and less instance of the comb leaving the rear bag and becoming airborn, a trait most SR BR stocks show when put under some recoil. The same load used in the SGY shot little to nil vertical in the MBR. Same action barrel scope etc, but vast change in the way it reacted during recoil. It's not how it looks, or what its made of, its how it reacts to recoil. Then the next recoil and so on. My judgement is the SGY fore end was too short placing the weight bias too far forward when using the pedestal rest that left the butt end light and swinging in the breeze and never tracking consistently in the vertical plane under recoil. Sounds easy to fix but with weight restrictions, velocity requirements and rules confinement its not always straightforward as we both know. There was not a great deal of weight difference between the two stocks but worlds apart in geometry. The fix was geometry.

Tooley wrote a very detailed, and long article over on BRC of what is required in a stock and how that led to his MBR design and subsequent clones. If you read it and look at the mathematics around the lever principles, torque and center of gravity effect, it will alter the perception of what is actually the physical requirement of a stock. It basically says, deliberately or not, the Scoville and clones geometry is wrong way Corrigan for something with recoil and long heavy barrel. A bit unfair as the US rules have very black and white measurements and angles for SR BR stocks. Nonetheless it is probably why none grace the winners lists at 1K with something running a bit of recoil (torque) like you do. If you go that route, the math says no and i wholeheartedly agree from lots of fails to my name. A stock to my mind is about right when it places the rifles balance point between the action screws when fully assembled. If the three contact surfaces are on plane vertically to the bore, the tracking is inline and not curved which is regarded as the death knell. Why i reckon stocks should be machined in a mill and not molded. Or angle adjustable as some latest offerings indicate the importance of this.

I think you may be chasing a phantom here Alan. Our range will never show the best of a rifle since the ground alterations and the illegal population growth down there in Mehico sent the planet off its axis fucking up our wind vectors. Scores are one thing, but small groups on our range are a distant memory. I've seen your guns over a long period. They're perfect. The range sucks.

There is of course a very simple fix to this Alan. Build a heavy gun. Then you will truly see how much the range sucks for 10 shots.

dg wrote: ↑Sat Mar 17, 2018 2:02 pm So, in the above situation, when shot free recoil, would it be correct to state ?????? that the only reactive forces opposing the generated torque would be through the combined effect of the left hand front rest contact area/point and the rear bag/rest’s contact with the base of the butt.

Therefore, given the above scenario, would it also be fair to state, that, to equal the resistance force applied by a 5.5 inch deep butt sitting in a snug fit rear bag, that the offset left hand forend would also have to be at least 5.5 inches wide (distance from the bore/axis centre line)