Electric harmonic barrel tuning

[DanGuy48]

Years ago (OK, decades) I shot smallbore, 4 position, 50ft. At some of the matches, I saw shooters adjusting small screws in the forend and watching whether a small battery powered light was on or off. Apparently they had determined, not sure how or by whom, a harmonic node along the length of the barrel. The two screws were at about 45 degrees off the center line. The first screw was turned in til it touched. The second screw was turned in until it just touched ( light on or flickering slightly). The first screw was then backed off until the light went off, and then turned in again until it also just completed the circuit. With these two metal points just barely touching the barrel, they supposedly induced a harmonic vibration, instead of random one, in the barrel and were considered to be an accuracy improvement. My coach said they were just trying to psych people out but it sounds reasonable. Has this type of tuning fallen into disfavor? I can't find anything on it anywhere.

 

[DanGuy48]

Mods, apologies for posting in wrong area, please move to appropriate forum.

 

[Kings X]

Yes they work.
This is all per-clamp on barrel tuners.
Today they mount the front sight base on the tuner base.
Search "electric barrel bedding" for more details.
The procedure was to chick each screw one click and shoot a group. Keep doing this until groups get small.
My BSA Martini Mark one likes 6 clicks.
Some 22 BR shooters are adding a weight just in front of the stock now. Does the same thing.

 

[BoydAllen]

The exotic electronic device was merely a powered continuity tester that did a better job, than feel through a screwdriver or wrench, of determining at what point bedding device screws made contact with the barrel. I remember thinking that I was about to read something really trick when I read the title of an article that mentioned electric bedding device. no such luck.

 

[STS]

And they were using wood stocks that would move some other direction with each passing rain shower. You could "tune" till you were blue in the face and come back the next day only to discover that all the effort yielded only empty cases and a need to do it all over again.

 

[Kings X]

Another reason we back them off before going into case. Wood also takes a "set" of left under tension.
Wood bedding also changed due to weather.

 

[xs hedspace]

I tried to tune a 22 Win 52 barrel with an oscilloscope, accelerometer, and microphone for registering the time the bullet left the barrel, and finding the null, or least movement setting for my tuner. No luck. Later I realized that I should be looking for an upward movement, to compensate for slow rounds that would print low on target. Sorta like the Brit 303 SMLE positive compensation bedding theory for LR work. Had to give the scope back when I retired. Should have kept it, nobody remenbered I had it---rats!