Finding the barrel vibration sweet spot

[TexasMac]

The latest edition of the Single Shot Exchange (SSE) magazine included an article titled, Minimizing Barrel Bounce off Cross Sticks – Finding the Sweet Spot. If you do not subscribe to the SSE and are interested in the details, I just posted the article at the following link: http://www.texas-mac.com/Minimizing_Bar ... _Spot.html

Wayne

[Perentie]

Thanks for posting that. I had not heard of the trick with the wire loops before.

[cat1870]

Very interesting. Thanks for the post.

[mdeland]

Good stuff Wayne, I did not know about the stethoscope method. Were do you get one suitable for checking this?

[ScrapMetal]

Very interesting article though I think there was a bit of a flaw in the testing done with the wire loops that could possibly explain the deviation from other methods.

When shooting from hand the receiver would act as "part of the barrel" Taking the receiver out of the equation by clamping it in a vise (just my instinct as I haven't tested it out) would most likely "shorten" the wavelength causing the wires to settle in spots that weren't "natural". Holding the rifle tightly in your hands would have some effect as well but not as much.

I think that if a person re-engineered how the rifle was held better results could be achieved. (Still an ingenious way of doing it.)

JMHO

-Ron

[TexasMac]

Good stuff Wayne, I did not know about the stethoscope method. Were do you get one suitable for checking this?

Any standard stethoscope will work. Amazon has a bunch & some are around $5. Of if you know someone that has a blood pressure kit.

Wayne

[TexasMac]

Very interesting article though I think there was a bit of a flaw in the testing done with the wire loops that could possibly explain the deviation from other methods.
When shooting from hand the receiver would act as "part of the barrel" Taking the receiver out of the equation by clamping it in a vise (just my instinct as I haven't tested it out) would most likely "shorten" the wavelength causing the wires to settle in spots that weren't "natural". Holding the rifle tightly in your hands would have some effect as well but not as much.
I think that if a person re-engineered how the rifle was held better results could be achieved. (Still an ingenious way of doing it.)
JMHO
-Ron

Ron,

Excellent comment. I'm about to determine the sweet spot on a new Browning .45-70 & will figure out a way to clamp the rifle by the receiver and by the stock to see if it makes a difference. BTW, I assume you noted in the article that there was no deviation with the Stevens 44 and it was held in a padded vice by the receiver as were the others.

Wayne

[SSShooter]

Am surprised that no one has mentioned holding the rifle muzzle down by the stock and tapping along the barrel with a small hammer (I use a small brass hammer so doesn't mar the barrel). The sound will go to a definite "thud" at the node(s). I remove the forearm wood & screw when doing so but will now do the same with the wood in place to see if I find any difference. A method that was prevalent in F-Class when I was shooting same. Quick & easy.

Wayne - would be interested in your results if you give it a try and see how it compares to your other methods. Forearm on & off.

[TexasMac]

Am surprised that no one has mentioned holding the rifle muzzle down by the stock and tapping along the barrel with a small hammer (I use a small brass hammer so doesn't mar the barrel). The sound will go to a definite "thud" at the node(s). I remove the forearm wood & screw when doing so but will now do the same with the wood in place to see if I find any difference. A method that was prevalent in F-Class when I was shooting same. Quick & easy.

Glenn, it's discussed in the article although I did not use a brass hammer which may be a better choice. Scroll down to • Feeling the vibrations:

Wayne

[SSShooter]

Yep. Overlooked that (feeling vs. hearing).
Did you do any comparisons with any of the methods between forearm on or off the barrel?

[TexasMac]

Yep. Overlooked that (feeling vs. hearing).
Did you do any comparisons with any of the methods between forearm on or off the barrel?

Nope, all testing was done with forearm & scopes attached which is the way I shoot all my rifles. Taking off the forearm or the scope may make a difference but I don't care since I'll never shoot it that way. I am interested in any possible differences clamping the rifle by the stock or some other method vs. the receiver will make since it would closer approximate actual shooting conditions.

Wayne

[ScrapMetal]

Ron,

Excellent comment. I'm about to determine the sweet spot on a new Browning .45-70 & will figure out a way to clamp the rifle by the receiver and by the stock to see if it makes a difference. BTW, I assume you noted in the article that there was no deviation with the Stevens 44 and it was held in a padded vice by the receiver as were the others.

Wayne

Wayne,

After giving it a bit more thought, the "perfect" way to hold the rifle would be to try and duplicate the conditions under which it would be shot at the range/in competition. I picture maybe a sandbag at the butt of the rifle and a "soft" grip in the hand position around the stock behind the receiver. Maybe some downward force on the end of the butt so the barrel can be free floating and the rifle supported at the "hand" position.

I have to re-iterate how I enjoyed the article and will be using the techniques written about to try and make my rifles more accurate.

Many thanks,

-Ron

[mdeland]

I found the dead spot on my match rifle using the technique of holding the rifle by the pistol grip, muzzle down and tapping the barrel with a rawhide hammer but it would be nice to confirm with the stethoscope in the horizontal shooting position as well.
I would be surprised if they agreed. Could you check this for me Wayne as I don't have a stethoscope?

[Coltsmoke]

I hold the rifle by the buttstock and let the rifle barrel hang down, place the side of the buttstock to my ear and tap down the barrel with a rubber hammer. I hear the vibration not necessarily the thud of a dead spot. Although the sound does change, the vibration completely comes to a stop at one point on the barrel, that is the spot I use. I like the wire and the powder test, I want to try that also.

[TexasMac]

OK Guys,

Based on recommendations I did some additional testing but with a Browning .45-70 that I'm about to shoot with ladder test loads for the 1st time. The rifle has a scope mounted with a Steve Earle rail. I tried two different rifle clamping methods as noted. The measurements are from the muzzle. And keep in mind that the Browning is designed with a floating forearm. Although it may rub against the barrel it's not mounted to the barrel but to an under-barrel hanger bolted to the front of the receiver which may be why the stethoscope method agreed with both clamping methods. BTW, the dancing wire technique best location is where the majority of wires congregated.

Rifle vice (clamped at rear of stock and resting on forearm)
Stethoscope method: 8.5”
Dancing wire method: 6.75” (best), 9.5” 2nd (best)
Machinist vice (clamped by only the receiver)
Stethoscope method: 8.5”
Dancing wire method: 6.5” (best), 9” (2nd best), 12” (3rd best)

So, I'm starting with the 8.5" location. And I ain't doing no more testing so you guys can take it from here.

Wayne