Shot "ring"?

[Telecomtodd]

First, I have to say how much I enjoy this forum. It gives me a chance to ask questions that even in the shooting hotbed where I live, I can't find answers.

Here's an interesting situation. My son mentioned one day that his 1913 "rings" when shot. When he has his cheek on the cheekpiece, through bone conductivity, he can hear a particular tone when he fires a round. He was having a hard time explaining what he was experiencing until he handed the rifle to me to shoot, and I heard it plainly. It's like a dull "booong" at about 800 hz. Reminds me of smacking a tuning fork on a table and hearing it ring. Barrel harmonics?

I bought another 1913 yesterday, but it was after considering whether a 2013 alum stock would have the same issue or be worse. My father had me call one of his shooting friends in Ohio who shoots a 2013...and it turns out he had experienced the same "ring" on his 2013! He had never heard anyone else mention it, and was a bit hesitant to ask anyone else if they heard the same tone, and I was the very first person to ask if he'd ever heard it. He originally thought it was a sight vibration, but put a different sight on the rifle and still heard it "ring".

This is NOT an April Fools posting if you were wondering, ha. Anyone else hear an Annie ring, and if you figured out what was causing it, please let me know. I'm thinking a Fudd harmonic do-hicky might help, but then wonder if it would be allowed in NCAA for my son's shooting. Perhaps a bloop tube connector collar would help dampen it?

Or maybe that's "Freedom Ring" and I should appreciate it...I attended a Friends of the NRA dinner this week, ha.

Todd Ellis

[Jordan F.]

Hi Todd,

I can't distinctively remember that noise while shooting my FWB smallbore but will check next time I shoot it (likely tomorrow). I don't see why it would be a huge deal because you have allreaady shot, unless it is messing up your follow through somehow. A fudd tuner, or hoehn, etc probably wouldn't work as they go onto the end of the barrel, where the sight is but on one of my guns I have a "Henrich Mid barrel tuner". This is a device that weighs about 7oz I believe that fits on the middle of the barrel. The middle of it is made of a vibration dampening material and it is suppose to reduce vibrations, etc. Maybe that would help? They are about $80.

Jordan

[Kiwi bob]

Ihad the same happen with my 1407 which was bedded into the wooden stock with hard resin. When I restocked it with an Anschutz aluminium with its soft bedding material the resonating had gone.

Kiwi bob

[bruce]

All 3 of the Anschutz rifles that I've owned have rung, to varying degrees, when mounted in a range of different stocks.
I doubt that it is having a detrimental effect on the shot.
As a matter of fact, hearing the ring consistently, shows that the cheek is applying the same pressure from shot to shot, and that you're following through every time as well.

[Shooting Kiwi]

I have a 1913 barrel / action mounted in a Kiwi-made alloy stock. The bedding material seems to be some sort of rigid, filled epoxy-like material. To get some idea of the gun's accuracy, I clamped it into the club's rigid vice, the rifle being clamped at the stock's fore-end and butt.

On firing, the ring could be heard across the range and the vibration could easily be felt by a hand on the vice. The frequency was, however, in the low hundreds of Hz, at a guess.

So, a lot of energy is fed from the action into the barrel, stock and, in this case, the vice. It is inconceivable that the barrel would vibrate similarly when shot from the shoulder. Note that I say similarly - I'm sure that the damping effect of a resilient suspension, compared to the vice, would not reduce the barrel vibration all that much.

And so one has all the fuss of trying to 'tune' the instrument for the tightest group by adjusting the acoustic coupling between the receiver and stock by torquing the wretched bolts. Not really a very clever design concept, is it?

[Telecomtodd]

This is a very interesting article...

http://www.precisionshooting.com/psm_2007_09_issue.html

And an interesting site: http://www.henrich3.com/smallbore_vib_cont.htm

And an interesting thread: http://www.perfectunion.com/vb/showthread.php?t=39601

Todd Ellis

[40xer]

Some ring...some don't.

In the benchrest rimfire game ... the accurate ones are the ones that don't.

Fordy

[Telecomtodd]

Fordy - the question remains, what causes it? Why do some have a loud ring, and some have a "thud" at the muzzle?

I'm trying to get my hands on a Henrich smallbore vibration eliminator, but I've left voice messages and e-mails with no answer yet.

[Shooting Kiwi]

The ringing is essentially poorly damped resonances excited by the bang. Spectral analysis shows many frequencies, showing that the thing vibrates in a complex way.

Really, (target) rifle design is fundamentally flawed because of the way the mass of the barrel and action is coupled to the stock. The bit where the (mainly horizontal) excitation originates (bolt face, chamber, etc.) is displaced vertically from the centre of mass of the rifle and the suspension of the rifle, be it arms or bench, etc.. This will therefore try to rotate the rifle in a vertical plane. The mass of the barrel resists this, but, of course, the barrel flexes, so it behaves a bit like a whip. The vibrations will spread forwards along the barrel and be reflected from its end. Likewise, vibrations are transmitted along the stock. There will be some reflection of energy at each change of section, change of material, each non-perfect mechanical joint and every interface between regions of different acoustic impedance. No doubt the reality is even more complex than this simplification.

The end result is that you have a structure which can ring like a bell, and then you hit it! No surprise it rings.

Barrel tuners add mass to regions of the barrel which vibrate most, making them harder to vibrate, thus reducing the amplitude and frequency of vibration. The position of the added mass along the barrel is therefore important.

I think a much better approach would be to try to damp the vibration by adding 'lossy' material to the right places on the barrel, etc.; no doubt someone has tried. Perhaps some tuners are really dampers. Think of striking a bell and then lowering it into water - that stops the ring pretty quickly. Lossy material converts vibration energy within itself into heat.

I believe that wood stocks may be preferable to metal stocks because (most) metal 'rings', whereas lumps of wood posess reasonable self-damping properties and are acoustically much more dead. (Of course this is not always true, particularly when one is thinking of wooden musical instruments, but wood is certainly lossier than alloy).

Does this help?

[Telecomtodd]

Gosh yes, this was exactly the type of response I was hoping to find.

My two areas of exploration were going to be adding a bloop tube (was going to do this anyways) thinking that the linking collar might add mass and thus bring the ring to the muzzle more efficiently. The second point was to add a Henrich vibration dampener, but I haven't been able to reach them yet; must be on holiday or something.

Thanks Kiwi! I do work with your bunch down on the south island that Sir Angus put together. They think it's a riot I can actually say "aluminium" rather than "aluminum".

Glad I bought a wood stock...

[Telecomtodd]

Dick Henrich called back today, a very nice and helpful guy. Sent him a check today for one of his units, we'll see how it goes!

[Richard Blackburn]

Yes, I get that too - Anschutz target 22 bedded in wood.

But is there a 'ring' when you dry fire using one of those plastic dry-firing things?

If so, part of the 'ring' at least must be coming from the trigger mechanism.

My Walther air rifle 'rings' on dry-fire, and so does my Morini CM162EL air pistol on dry fire (though only faintly, and you have to have it next to your ear to hear it). Same with my wife's Steyr air pistol. Though this could be due to the 'twang' of all those springs.

Richard

[Telecomtodd]

No ring with snap caps, just a soft click. The ring will last about 1/4 - 1/2 second, something like that, and then settles out. It only happens when you live fire.

Todd Ellis

[Telecomtodd]

Here's a preliminary update on the Henrich smallbore vibration dampener. In short, it works. I started shooting my new 1913 (it's actually a little tighter than my son's I believe) and shot some rounds with it. I was hearing a thump with my rifle instead of a ring, but now with the dampener, I'm hearing a very soft thud and the rifle is extremely smooth. I placed it just before the muzzle "bulge". End result - worth the money, and I'll do more precise experiments with it as I do more shooting with this new rifle.

Todd Ellis

[Telecomtodd]

More real-world input...last night we put the Henrich Smallbore Vibration device on my son's 1913. He's been concentrating on offhand. He immediately sensed the improved smoothness of firing - no ring. He also liked the extra weight at the barrel - that amazed me too. We ended up adding two of the optional weights and his scores increased and groups decreased. How much of a change? His ability to hit 10s at 50 yards had been difficult; now he's hitting no less than 8s and had several 10s with a couple of Xs. He was so happy with the results that I thought he was going to shoot all of the brick of SK Match ammo I brought to the range!

Here's the one bad point about all of this. He liked using it so much, now he won't give it back to me. I guess I'll have order another one from Dick.