My centerfire friends

K

Kathy

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My centerfire friends:

Do any of you have any idea how long the barrel vibrates, say with a 6PPC case with a bullet at 3200 FPS, after the round is fired? Say with a standard heavy varmint taper barrel, 22 inches long, as an example....

Does the barrel vibrate for a second, half a second, two seconds, more, less.........?

In other words, how long after you fire a round, does the barrel come back stationary, completely, no vibrations?

Any ideas at all?

Your friend, Bill Calfee
 
Bill,
I have heard that in the case of a rapidly fired rail gun ( in the specified caliber) that shots can be influenced by residual vibration from a previous shot. As a matter of fact, I know of one fellow, who is an accomplished competitior, who wraps his rail barrels, with vibration damping material, to prevent the problem.
Boyd
 
It depends entirely on the type of stock and bedding method.

As a typical round number, I'll give it 1.5 seconds in my rifles.

It has about as much to do with my next shot as does the cutting oil I dump on the ways of the lathe has to do with how a drill works.

Now. My question to you is, do you have any idea how far, in thousanths of an inch, the end of the barrel remains moving upon firing a shot 3 or 4 seconds after firing the last shot. In other words 4 seconds after a shot is fired, how far is the end of a LV muzzle moving? .001? .002? any guesses?

--------------------------------------EDIT
In fact, just to show that I'm not attempting to lure hard earned information from you, or steal any secrets, I'll even modify that question/request to this.

Have YOU ever personally tested or witnessed the testing which quantified the lateral/vertical/angular movement of a muzzle due to vibration? I'm not interested in knowing the amount of movement you or your aquaintances found, only IF you have actually tested this for yourself. This does not include reading someone elses theory of this movement in a book. I am talking about down hard facts about how far they move.

You're welcome to post here, a YES or a NO. No other info required. If you do not wish to allow others to know this yet, you're welcome to PM me here on the board by clicking on my name and sending private message. Your answer, if sent by pm will be kept confidential and no further discussion will come of it from me.

Given that you have been years in study of barrel harmonics, I'm just going to guess that the answer to this must be yes because in my thinking, this is THE SINGLE most important piece of basic information required to make any assumptions concerning barrel vibration. I just find it odd that this dimension has never in my reading, ever been discussed.

By the way, I recently offered the use of the very equipment needed to do such a test and was turned down.
 
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Bill

Can't give any info on a barrel taper such as a typical HV, but I can say this about the 1.450 barrels that we use on our Rail Guns.
Keep in mind, only about 14 inches of it is actually sticking out of the typical barrel block. We can shoot these things at a rate of at least 1 round every 2.5 seconds, some faster. If the barrel still had residule vibrations from the previous round, I doubt we could get them to stack one round on top of another the way they do.
One interesting thing I have found out is when you put a tuner on the end of a Rail Gun barrel, it goes crazy when you try to shoot it really fast. I really do not have much of an explanation for this, as you can make it shoot phenominolly well with a tuner, (we were using about 25 ounces on that heavy of a barrel), at a slow methodical pace, say one round every 3 to 4 seconds. I think the tuner actually keeps the barrel from settling down when trying to shoot fast. But that is just a hunch.
As far as the lighter barrels, I have seen shooters who can shoot really fast rack five shots in about 15 seconds with a bag gun. If there was much residule vibration left after each shot, I doubt they could expect the bullets to go on top of one another.
Maybe you, or perhaps Varmint Al, could figure out what is really going on.......jackie
 
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Lynn, thanks and I'll just consider the answer to be at least a half a yes. unless of course those indicator readings were taken while firing a rifle in which case it's a full yes.

I say a half yes if the barrel was being hit with an object, rather than fired.

I do not keep old magazines so that's out for me. I would not have had any PS before late 04 anyhow. While an indicator would give an "indication" excuse the pun, the needle would be bouncing so only a portion of the indicated movement could be considered real. Indicate a rough part in a lathe and watch the needle when the part is turning. It's tough to quantify.

I still think that monitoring the movement electronically and attempting to correlate the result with a target would be of far more use than trial and error with weights and systems.

Good enough then. Thanks again.

Jackie, that's interesting that the rate of fire isn't faster. Or is it for some folks? I've actually done faster than 2.5/shot with my bag gun for 10 shots and it's a 30 cal magnum. I've seen under 20 seconds (10 sh) but rarely, and that's still on sand.
 
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aaah, again, the black art of harmonics. I love reading through this stuff. Very intersting.

The higher the viscosity of the fluid, a vibrating device is submerged in the faster energy is dissipated. So this will change significantly day to day, location to location, altitude etc.

So, the question cannot be answered for several reasons. The most obvious is that who can tell between moving and stationary with the naked eye? I'm not seeing many accellerometers dangling from the barrels at my range.

I do have experience vibration testing and I do have access to some equipment if someone is really really that interested....I do not have a 6ppc, but I do have a 30 BR!!!

Ben
 
By my eyes (blurred by catarachs ), the scope keeps vibrating after the barrel quits. I've run a 1,000 HG back to the target & felt the scope tube still vibrating, and seen the dot still "vibrating." Not much -- not enough to affect the decision to shoot -- except I have noticed that when shooting a 1K HG that returns to battery 80% of the time, it shoot a little better if I shoot a little slower.
 
Dial indicator

Id love to see that ! Yes I would ..

Use a rail gun , fix a dial indicator to the muzle , have it pre-loaded / sprung .

And use a high speed camera to watch the dial indicator ...

Could the pre loaded dial indicator keep up with the vibrations ?
How many vibrations are we talking about before the bullet leaves the barrel ?

Hmmmm , anyone want to send it to Mythbusters ? :p

Matt
 
MattK said:
Id love to see that ! Yes I would ..

Use a rail gun , fix a dial indicator to the muzle , have it pre-loaded / sprung .

And use a high speed camera to watch the dial indicator ...

Could the pre loaded dial indicator keep up with the vibrations ?
How many vibrations are we talking about before the bullet leaves the barrel ?

Hmmmm , anyone want to send it to Mythbusters ? :p

Matt
Click to expand...

And as for movement , thats easy , just a bit of math ... If the flier is 0.100inches out at 100 Meters , how much did the barrel need to move ?

Come on math guys ,
 
Ah

Grass hopper the barrel never seizes to vibrate due to the butterfly effect.
 
A little information, I have a test fixture that i built 2 years ago to tune a rimfire rifle in,It uses 2 Min,Max electronic indicators to measure the actual barrel movement in two opposite directions at the same time,I can also measure the actual time that a barrel vibrates until it stops,I have never tried a centerfire rifle in this fixture,so no opinion on this,But you would really be suprised at the variables involved,My reason for wanting to see when the barrel quit moving was the fact that i have & can shoot a 25 Bull target in under 4 minutes & i wanted to see if my barrel was moving on the next shot & what effect it plays on the Rifles agging ability. I know a lot of the answers There are ways to keep the barrel vibrations down to a miminum as not to affect the rifles true tune,I will not put any of this data on this website,There are certain people that i do not want to have this info.BILL
 
Answers?

That there's the problem. :confused:
There are certain people that i do not want to have this info.BILL
Click to expand...
This isn't NASCAR with million dollar purses, why would you feel the need not to share info. And we wonder why we can't build our sport up. If we all had million dollar R&D budgets it would be a different situation.
 
This is another one of those questions asked without a good definition of what is really being asked, and really raises other questions. For example what is meant by "no vibration" - is it 1/100 of what was there at the start or is it 1/10000? If the vibration decays by 1/2 each cycle then how many cycles will it take to drop to zero? (Bill, ponder on this for a while because this is kinda the way it works.)

Then if the vibration drops to 1/10 what it was at the start will this be enough to affect bullet flight? If it gets down to 1/1000, is this for all practical purposes, zero and will have no effect on the bullet?

If you want a for-all-practical-purposes, down to earth engineering answer, then the answer is the vibration stops immediately. If you want a correct scientific type answer then the barrel never stops vibrating until acted on by another force. If you want an answer determined by measurement then you must specify just how sensitive you want the instruments to be, and below this sensitivity constitutes "no vibration"
 
Francis,
A friend came back from Tony School convinced that he was henceforth going to run. I tried to tell him that while running is great, when conditions allow, that some conditions are not condusive to that technique. He was not having any of it. Subsiquently he attended a match a St. Louis that was also attended by Mr. Boyer. After trying to run his groups all weekend, my friend (who has done well in other matches) was not a happy camper. After the match Tony commented to him that he had picked all weekend.
Boyd
 
My friends

My friends:

A million things going on right now......been running tests about this subject.....I've posted on both the rimfire and centerfire forums about this issue...

tomorrow I will post some test results from today....

What does all this mean? I ain't sure.........I've been doing this for 34 years and ain't never run on this before, at least not that I noticed it......

I will probably post on the rimfire forum.......which means you might need to look there, if you are at all interested.....or someone who knows how could put it over here.......

Real quick: how long does a "rimfire barrel" vibrate after being fired, or bumped...........at least 8 seconds.....a centerfire?????????

Your friend, Bill Calfee
 
Seemingly, My rail gun barrel vibrates more than HV,s. Almost
anything causes it. To much mass in the barrel, mounted to ridgid
No taper, I am curious
 
Kathy said:
Real quick: how long does a "rimfire barrel" vibrate after being fired, or bumped...........at least 8 seconds.....a centerfire?????????

Your friend, Bill Calfee
Click to expand...
Bill
It's just like the question "how big does the muzzle device for this barrel need to be" - It ain't always the same.
 
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