TUNERS,, "Oh No, not again", you say

[Gene Beggs]

TUNERS,,,Oh no,, not again

"Howdy" from West Texas and, Happy Fourth of July !

Since the terrorist attack of 9/11 this day has even greater significance to me. God, please save and richly bless America.


Now that we have the most important part of the thread out of the way, let's move on to more mundane and trivial matters like tuners.

Hey, wait, don't leave, this is going to be interesting, I promise.

The discussion of tuners has dominated conversation here on BR Central in recent months. Much progress has been made but there are still a great number of shooters who have no clue about how to use a tuner. Most are now convinced that they work, but few really understand how and why they work. Perhaps this thread will help shed some light on the subject.

In order to understand how tuners work, you must first understand a fact of life; barrels vibrate when fired. Yep, all barrels vibrate, primarily in the vertical plane when fired and this vibration is in progress as the bullet travels down the bore. It is not necessary to understand the details of this vibration; the only thing you must know is that the muzzle is vibrating up and down and as such, is slowing and coming to a dead stop at both the top and bottom of its swing. It is at one or the other of these 'stops' that you want your bullets exiting because small variations in muzzle velocity will have the least effect on verticle dispersion.

With the typical benchrest rifle, the frequency of the barrel is such that when the rifle is perfectly 'in tune', an increase OR decrease of 60 fps in muzzle velocity will throw the rifle completely out of tune! That's right, expressed in fps, the peaks and valleys of the sine wave are 120 fps apart. What really counts is not so much the muzzle velocity but the elapsed time, the in-bore time.

We won't throw too much at you at a time and until everyone thoroughly understands what I've said so far, we will not move on. Don't be discouraged, it is not complicated at all. This time next year, if you are not taking advantage of a good tuner, you will certainly be at a disadvantage shooting against those who are. We can't let ole Jackie Schmidt keep kickin' everyone's behind with his tuner; can we?

Later,

Gene Beggs

 

[John Kielly]

With the typical benchrest rifle, the frequency of the barrel is such that when the rifle is perfectly 'in tune', an increase OR decrease of 60 fps in muzzle velocity will throw the rifle completely out of tune! That's right, expressed in fps, the peaks and valleys of the sine wave are 120 fps apart. What really counts is not so much the muzzle velocity but the elapsed time, the in-bore time.

Gene,

I presume that you are talking of the "standard" 6mm loadings used in centrefire benchrest. Questions:

• What velocity spread is needed to achieve a tuned load, or are you defining a tuned node as one that occurs when a particular powder range shoots closest anyway?
  
• Have you experimented with calibres other than 6 mm?
  
• Can you tune that load that is 60 fps out of optimum, that is modify the harmonics to cause that sine wave to switch 90 degrees?

John

 

[Edwin D]

If you win each week you stub your toe, then by all means, STUB YOUR TOE!

 

[Gene Beggs]

Gene,

I presume that you are talking of the "standard" 6mm loadings used in centrefire benchrest. Questions:

• What velocity spread is needed to achieve a tuned load, or are you defining a tuned node as one that occurs when a particular powder range shoots closest anyway?
  
• Have you experimented with calibres other than 6 mm?
  
• Can you tune that load that is 60 fps out of optimum, that is modify the harmonics to cause that sine wave to switch 90 degrees?

John

John, I have experimented at great length with the 6ppc, the 220 Beggs and the 6mm Beggs cartridges. They all respond to my tuner in the same way.

I believe the remainder of your questions will be answered in the posts that follow.

Gene Beggs

 

[Gene Beggs]

For the sake of discussion, let's assume that I installed a tuner on Bubba's favorite sporter yesterday. The rifle is a Kelbly Panda with a 23 inch Krieger barrel chambered in 6ppc. We are back at the range this morning to learn how to use it. I asked Bubba, "Do you have any questions before we begin? He said, "Yeah, several."

"Now Beggs, you have to understand, I'm from the old school. I think this tuner stuff is a bunch of hogwash. You're gonna' have to show me! First of all, explain this thing you put on the muzzle of my rifle."

Bubba, the tuner consists of two, threaded, stainless steel collars, .250 thick and 1.800 in diameter. The centers are drilled and threaded 15/16 X 28 TPI. The outer diameter of each collar is drilled in four places to accept a small rod, which is used to tighten the collars against each other like jam nuts. Total weight installed is four ounces. Each revolution results in .036 movement fore and aft.

Bubba rubbed his chin and said, "Alright, I see, but just how in 'ell can something that simple 'tune' a barrel?"

Good question Bubba, let me explain. The tuner acts just like the 'steel' on a steel guitar. As the musician moves the steel fore and aft on the strings the tone rises and falls. The 'steel', in effect, changes the length of the string. The shorter the string, the higher the pitch. The tuner on our barrel acts the same way. Screw the tuner toward the breach end of the barrel and you raise the frequency and vice versa.

"Okay, I'm with you so far" said Bubba, "but how much do You move the tuner and which way?"

Very simple, you can move the tuner either way. That's right, the most you can be out of tune is one half turn, a half turn in either direction. "Aw 'ell" Bubba snarled. "You're gonna' have to show me." Okay, come on over here to the 100 yard firing line.

Bubba, we have the rifle clean and the tuner zeroed. By 'zeroed' I mean that back in the loading area, we loosened the tuner and turned it all the way in to the end of the threads and backed it out one revolution and placed the reference mark at 12 o'clock. We have the cartridges loaded with 29 grains of Vit., N133 which is your pet load. If we were tuning by changing the powder charge, we know we could not possibly be more than .6 grains out of tune but from now on we will NEVER vary the powder charge. We will do all tuning with the tuner.

Okay Bubba, fire a couple of shots and adjust the scope so the point of impact is to your liking then fire a three shot group on the sighter. Don't worry much about reading the flags, just pick a general condition and run the shots. Okay, that's good. Notice that your group has two bullet holes of vertical, the rifle is completely out of tune. Now what did I tell you about a completely out of tune condition? That's right, it takes a half turn in either direction to bring the rifle into tune. So, remove the bolt and slide the rifle out of the bags and place it on the bench beside you so you can reach the tuner. Remember, the rules say we must remove the bolt and remain seated when we adjust the tuner at the bench. So, take the two little 'Tommy bars' I gave you and loosen the tuner. Now, rotate the reference mark to the 6:00 o'clock position and retighten the collars. Yeah, either direction.

Bubba's next three shots went thru the same hole! His eyes were as wide as silver dollars as he turned and asked, "You mean that's all there is to it? Well I'll be a son of a ,,,,,,,."

Bubba was silent as we walked back to the loading area, I could tell he was thinking seriously about something. As we cleaned the rifle, he said, "Okay Beggs, Mr Wise A$$ know-it-all, tell me what happens when the atmospheric conditions change? What do we do when the temperature gets up to 90 degrees and humidity goes down to 21 percent? Huh? Answer me that!" How much do we move the tuner? And which way?"

We will get into that next time.

Later,

Gene Beggs

 

[earl39]

not again you say

HAPPY 4th to you all.

ok Gene, i know this has been asked somewhere but will the tuners work the same for 1000 yard as they do for 100 yard or will the difference in speed from shot to shot prevent the tuner from being as effective?


gary

 

[nonliberal]

"
What really counts is not so much the muzzle velocity but the elapsed time, the in-bore time.

Gene Beggs

I found this to be true last weekend when experimenting with opening up flash holes in small primer pockets starting with .059 then .062,.064,.067,.070,.073,.075 and .080 (large primer flash hole size).

With all loads being excactly the same, the groups would clearly open and close with different size flash holes (It acted about the same way incremental seating depth changes does). The thing is muzzle velocity didnt really change at all. I concluded that the speed of ignition was effecting elapsed time in the bore, but by the time the bullet left the barrel all the powder had still burned to create the same velocity.

The flash hole size just changed the in bore timing and it made a huge difference. I see clearly how a tuner would work as you describe.

 

[Gene Beggs]

HAPPY 4th to you all.

ok Gene, i know this has been asked somewhere but will the tuners work the same for 1000 yard as they do for 100 yard or will the difference in speed from shot to shot prevent the tuner from being as effective?


gary

Gary, I wish I could answer your question but I have no experience with thousand yard shooting. My experience during the past twenty years has all been with 100/200 yard group shooting. I rely on being able to see the bullet holes in the sighter. This tells me what I need to do to the tuner in order to achieve optimum tune. I would be lost at 1000 yards, because I assume you cannot see your bullet holes at that range.

Gene Beggs

 

[tim in tx]

gary sir

i test shooting into dirt or a steel white gong and can see every shot at impact but what i see is a 3oz weight that is adjustable will bring the moa in at 100yds ,then it will certainly make the 1000yds tighter as well in the respect of moa,so you can alway come back to tune by a simple turn of the tuner, the velocites are generally level with most 1000yds shooters so the beggs tuner can work,from what i have tested gene is right on the money, with a 3oz adjustable weight you will never be more than a quarter of a turn out of tune whether it be 100yds or 1000yds ,the long range tuner can correct for velocity variance but the barrel has to be whippy by extending the length and weight of the barrel muzzle and with a taper to get the right amount of whip to completely correct the velocity variance,just 2 different ways of tuning but both are effective for either yardage.genes tuner seems it is much easier to get working ,the good thing about genes tuners design is that if your velocites are level and you tune it in at 100yds then turn around and shoot any yardage you want and it will still group tight without changing your tuner for the particular yardage. hope this helps sir. tim in tx

 

[Tony C]

Informative thread Gene.

Thanks,
Tony

 

[jackie schmidt]

Gene

I believe in my Tuners, and I use them.
But, as you saw at this last match at Midland, the best of everything is little help if you can't read the switches in a 15-25 mph wind at 200 yards.
I have made myself a promise. From now on, my predominate shooting practice will be at 200 yards........jackie

 

[Gene Beggs]

Hi Jackie

It was nice to see you this past weekend at Midland. You did some fine shooting in very difficult conditions. I agree with you, the best rifle in the world, tuned to perfection cannot help us read those tricky, switchy conditions like we had Sunday.

Again, good to see you. Keep in touch.

Gene Beggs

 

[earl39]

thx Gene and Tim

this bears some thought on my part now. am thinking about trying a tuner but also think i will wait till i get ready to replace my barrel and put it on the old one and see how it works before i put one on a new barrel and find i don't like it or that it is all me and nothing is out of whack with the barrel (the latter is highly possible) as this is just my second full year of 1000 yard shooting.