I've set up an experimental rubber bonded barrel weight on my next .284W barrel (club gun). The intention is to try and increase the node length as weights do but at the same time absorb some of the smaller harmonics..
I've put this together, but I think I've made a mistake and need to remove it and re-bond it.
The barrel is a straight profile 1.125". I've mounted the weight flush with the 11 degree crown edge. I'm thinking now that I should have set it back an inch just to make sure that it doesn't cause any turbulence with the exiting gases.
Is the 1.125" crown enough to get the bullet away cleanly, or should I remove it and set back an inch?
I think ur on a winner ! My experimentation had also flush with the barrel. An inch back can have a large effect on harmonics , adversely ! Try it before u stuff with it ! Like Cam said!
Denis, the muzzle weight you have chosen does few things. The primary function of its weight reduces its amplitude of barrel lift and so it has the most leverage at the muzzle unless you add extra weight or some forward of the muzzle. So leave it there. The rubber decouples the weight from the barrel to dampen further lower order vibrations but also returning vibrations that may distort the muzzle shape before bullet exit with stacked waves. There is no way gases will be distorted. Go test it.
I recently made an aluminium stock with rubber whiskers to further dampen vibration. I notice your gear hasn’t got whiskers on it. Top job.
Thanks for your input Cam, Graham, Brad and David. I'll test it the way it is and see how the results stack up. If I have any issues. I'll re-position the weight before I determined that this system doesn't work.
Thanks for the little clappy man David. Got me chuffed.
I've set up an experimental rubber bonded barrel weight on my next .284W barrel (club gun). The intention is to try and increase the node length as weights do but at the same time absorb some of the smaller harmonics..
I've put this together, but I think I've made a mistake and need to remove it and re-bond it.
The barrel is a straight profile 1.125". I've mounted the weight flush with the 11 degree crown edge. I'm thinking now that I should have set it back an inch just to make sure that it doesn't cause any turbulence with the exiting gases.
Is the 1.125" crown enough to get the bullet away cleanly, or should I remove it and set back an inch?
Thanks..
may i ask what rubber bonding material you are using for this?
I've set up an experimental rubber bonded barrel weight on my next .284W barrel (club gun). The intention is to try and increase the node length as weights do but at the same time absorb some of the smaller harmonics..
I've put this together, but I think I've made a mistake and need to remove it and re-bond it.
The barrel is a straight profile 1.125". I've mounted the weight flush with the 11 degree crown edge. I'm thinking now that I should have set it back an inch just to make sure that it doesn't cause any turbulence with the exiting gases.
Is the 1.125" crown enough to get the bullet away cleanly, or should I remove it and set back an inch?
Thanks..
may i ask what rubber bonding material you are using for this?
Hi Dennis, I cannot see how having the weight flush is going to upset anything. I have been playing around with recessed crowns for awhile and found no problems with up to 1/2 inch recess and 1/2 inch dia. I have now gone to the "Purdy Prescription" barrel tune where one can have up to 1 1/2 inch of protrusion. What I did find with this method is that you needed a bigger dia. hole in the tuner. I started off with a 16mm hole as I used on R/F rifles but without success. I then tried 25mm hole and it worked. I believe that with the smaller hole and length that the gasses upset the projectile after it exited the barrel by having the gasses restricted. With the bigger hole it keeps the gasses away from the projectile as it exits the barrel. That is my theory as I found the bigger hole to work. I would leave it where it is as the gasses are travelling foreward and should and should not impact on it. Cheers, Trevor.
Shane, it may be a little more fiddly to install evenly but do-able. This is a 32" barrel so it has some leverage where it is.
I guess a fiddly aspect to rubber bonding is that the thickness of the bonding layer and then also the surface area that the bonding layer has will change the amount that the weight moves. A thicker layer or less surface area due to 1/4 of the weight over hanging might allow more movement.
I'm sure that if this systems works there will be an ideal amount of weight and movement from the weight, for each barrel. Not enough may not be effective, too much may cause more inconsistencies???? If it works, it could take quite a few trials to see the most effective setup.
A rubber bonded weight might change the way torque and recoil feel too as the weight might respond slower than the barrel initially dampening and then accelerating??? Maybe not enough movement or weight for that kind of effect.
The reason that I wanted to try this system is that being a mechanic and seeing how effective harmonic balancers are on the end of an engine crank shaft, I thought the principal may work here also.
Purely speculation and experimental at this stage.
Trev, thanks for your advice and experience. Definitely makes me feel a more confident.
Denis I mentioned the forward idea as all the adjustable tuners work forward of the muzzle. Your introduction of the rubber bonding gasket sets other interesting issues to play and consider? I have been using adjustable tuners for about 8 years and am convinced of their usefulness if one can afford the weight. One comment I can make is that the exit internal needs to be an expanding cone type. If that makes sense? I have seen this firstly on M14 National Match flash hiders over 30 years ago. The Armourers of the day opened them up to a progressively larger diameter towards the exit. Rather than a parallel exit as on the standard rifles which did not give as good accuracy as the National Match spec. Shane
Shane the conical ID for an accessory over hanging the muzzle is an interesting point. I haven't thought much about over hanging bits in the past, but it makes sense.
That could be compared to an area of mechanics as well in terms of cylinder heads that have ports opened up and matched to the manifold ports for smooth flow and less turbulence.
In any situation that you have a smaller volume area suddenly open up into a bigger volume area with the same amount of gas travelling through, that will cause the gas to suddenly slow down and probably increase pressure only at that specific point as it fills the larger volume. That might be the turbulence. A taper would control that more evenly. Its the opposite effect of a venturi (orifice shaped like an hour glass) such as those found in carburettors that cause the air running through them to speed up which creates a low pressure (vacuum in carby case) in the centre of the venturi. This is what allows vacuum advance on old points distributors when the throttle is open and no manifold vacuum is present.
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