Laminate vs composite stocks

[BoydAllen]

On the vibration issue, many years ago, I was at the Visalia range during a practice day before a short range bench match, when I came across one of the competitors who was observing the vibration of his rifle barrel muzzle with the aid of a transducer that was taped to it with electrical tape, feeding into some sort of recording oscilloscope set up on the adjacent bench. The fellow, Don Jackson, was an actual scientist by trade. He used to post on Benchrest Central under the screen name of Don from Redondo. (He lived in Redondo Beach in southern California.) His rifle had a Panda action, which allowed for easy variation in ring position. Looking at his setup, I asked him whether the position of the rings on the action, and the scope in the rings affected barrel vibration, He said that they did. Personally, I think that vibration damping is a lot more important to the highest level of accuracy than many people realize, and that a setup like what he was using would be useful for making comparisons. Another fellow who experimented extensively in this area was Harold Vaughn, author of Rifle Accuracy Facts, which is now available for free on line. I have a paperback copy that I bought when it was first published. Recently, Alex Wheeler has done quite a bit of excellent work comparing stocks of different stiffnesses and I believe that his conclusion was that extreme stiffness is not a virtue, based on actual testing.

 

[Bc'z]

On the vibration issue, many years ago, I was at the Visalia range during a practice day before a short range bench match, when I came across one of the competitors who was observing the vibration of his rifle barrel muzzle with the aid of a transducer that was taped to it with electrical tape, feeding into some sort of recording oscilloscope set up on the adjacent bench. The fellow, Don Jackson, was an actual scientist by trade. He used to post on Benchrest Central under the screen name of Don from Redondo. (He lived in Redondo Beach in southern California.) His rifle had a Panda action, which allowed for easy variation in ring position. Looking at his setup, I asked him whether the position of the rings on the action, and the scope in the rings affected barrel vibration, He said that they did. Personally, I think that vibration damping is a lot more important to the highest level of accuracy than many people realize, and that a setup like what he was using would be useful for making comparisons. Another fellow who experimented extensively in this area was Harold Vaughn, author of Rifle Accuracy Facts, which is now available for free on line. I have a paperback copy that I bought when it was first published. Recently, Alex Wheeler has done quite a bit of excellent work comparing stocks of different stiffnesses and I believe that his conclusion was that extreme stiffness is not a virtue, based on actual testing.

I am no expert on this subject of dampening or harmonics. I have however have had numerous conversations with stock makers and shooter about the benefits of torified maple in how it tones down the vibration/harmonics of the shot.
It would be nice to see something scientific of this using different stocks of the same design but with different types of wood used in thier construction, along with the use of CF stringers vs no CF.
Very interesting topic!!

 

[ELR LVR]

Short range, low profile, flat planed stocks are/were very popular for making weight requirements. However, a common complaint with some was the vibration from recoil impulse. These carbon fiber stocks with the most vibration seemed to be the ones with the lowest ratio of wood core. How many different brands have you shot?

So far my experience with Carbon fiber was not a laminate with wood
but with a full carbon fiber chassis (MDT HNT26)
I built a light hunting rifle in .284 Win and with scope weighed 10 lbs
I expected it to punch my shoulder harder than it did
Were it a wood stock, the recoil would have started to weigh on ya at about 20 rounds
it was very pleasant to shoot and can only attribute the light weight of the rifle and the lightness of felt recoil to be in the carbon chassis, I kept thinking, "when am I going to start feeling the shots build up in my shoulder?"
---
as a side note, back when carbon fiber bicycle frames first got fielded, that was a big selling point for them
in that they "Absorbed" a lot of road shock while still being relatively stiff.
Absorbed shock Moreso than aluminum framed bikes.
I was a bicycle mechanic for several years so have tested the difference and can say
While the Carbon Fiber was a little more "flexy", that yes carbon fiber was much more forgiving while Aluminum transmitted much more vibrations
---
However, I did not find the carbon chassis to be any more flexy than most standard stocks including fiberglass, which is more dependent upon it's shape and wall thickness.
Felt recoil of that Carbon Chassis gun felt more like a 22-250 than a .284

 

[ELR LVR]

On the vibration issue, many years ago, I was at the Visalia range during a practice day before a short range bench match, when I came across one of the competitors who was observing the vibration of his rifle barrel muzzle with the aid of a transducer that was taped to it with electrical tape, feeding into some sort of recording oscilloscope set up on the adjacent bench. The fellow, Don Jackson, was an actual scientist by trade. He used to post on Benchrest Central under the screen name of Don from Redondo. (He lived in Redondo Beach in southern California.) His rifle had a Panda action, which allowed for easy variation in ring position. Looking at his setup, I asked him whether the position of the rings on the action, and the scope in the rings affected barrel vibration, He said that they did. Personally, I think that vibration damping is a lot more important to the highest level of accuracy than many people realize, and that a setup like what he was using would be useful for making comparisons. Another fellow who experimented extensively in this area was Harold Vaughn, author of Rifle Accuracy Facts, which is now available for free on line. I have a paperback copy that I bought when it was first published. Recently, Alex Wheeler has done quite a bit of excellent work comparing stocks of different stiffnesses and I believe that his conclusion was that extreme stiffness is not a virtue, based on actual testing.

Agreed here,
every single little thing affects the vibrations of the rifle as a whole
---
I once read a paper of a guy who conducted a study similar to what you are decribing Don did with
his O-Scope
He measured the same thing on a gun with several transducers in various places
measuring things like
Action Flex due to barrel weight
Barrel Vibration etc
it was a very thorough and some 40 pages of testing and results
---
He determined that even adding 1 simple 6-48 tapped hole (say for a scope base)
to the action cause the whole action to flex more and change vibration of the assembly

 

[Fast14riot]

The bit of info I know about torrefaction is that it reduces damping by eliminating resins, sugars, pitch and other viscous materials within the structure of the wood. It improves sound transmission (vibrational waves) and reportedly lightens and improves strength. What it is, is an artificial aging process. 400 year old violins are still being played and they were made with reclaimed wood to begin with.

The change in the wood aging is not linear, but more closely to logarithmic, the process slows down greatly with time. I think what torrefaction does for a rifle stock is it allows the entire stock to act upon the vibration through its design and thus spreads the vibration out over the entire platform. Letting the entire fore end act as a tuned lever, like a composite stock does through geometry, with the action and butt dissipating that energy due to mass. This is also why rifle balance is important, and I believe that weight distribution can make up for deficiencies in stock material and/or design.

I like to think of the fore end as a sympathetic resonator. I haven't been able to physically measure and test my theory yet, but my armchair engineering on the topic makes sense superficially.