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[Orr89rocz]

Are there or have there been any test rigs developed with say a 6-10” diameter barrel to make it as rigid as possible and to take harmonics out of the equation? Then test only powder charge increments and pressure traces to see how the combustion dynamics change? What is the largest barrel diameter used in competition, 2 inch?

I have heard of structured barrels, but dont see them often. They are supposed to help reduce harmonics I believe. Anyone play with those?

 

[JFrank]

Not sure I would want to reduce harmonics. Is that even a thing !

 

[gunsandgunsmithing]

Years back, tests were done with the barrel set in concrete. Bottom line is it shot terribly. Getting rid of the harmonic aspect has been proven not to work. So what's left is to harness it and better manage the harmonics to our advantage. Is there an option I'm overlooking? Oh, I guess just disregarding them is an option too.

 

[jackieschmidt]

Are there or have there been any test rigs developed with say a 6-10” diameter barrel to make it as rigid as possible and to take harmonics out of the equation? Then test only powder charge increments and pressure traces to see how the combustion dynamics change? What is the largest barrel diameter used in competition, 2 inch?

I have heard of structured barrels, but dont see them often. They are supposed to help reduce harmonics I believe. Anyone play with those?

When I first built my Rail Gun back in 1998, I decided to install the barrel in a tube that had a 1.750 ID and a 2 1/8 OD. The 1.450 blank was centered in the tube with alignment rings. The space was filled with pourable Devcon.

That barrel was as ”dead” as you could get it. When you tapped on it, it had all of the resonance of a piece of wood.

It was pretty close to what you are calling a structured barrel.

It shot well enough to win the NBRSA 100 yd Nationals in 2000, The Texas State, and the Gulf Coast Region Unlimited, where it shot Five 10 shot group Agg of .213.

But, I had to tune that thing just like my LV. In fact, it shot the same load.

This lead me to believe that when achieving the kind of extreme precision that we do in Short Range Group, there is a heck of a lot more going on than just barrel harmonics.

Here is a picture of me, (it got water damaged) with the Rail Gun at the Nationals in 2000. You can see the barrel in the tube.