Now, a tuner question

[Pete Wass]

I have had tuners fitted to 4 of my Benchrest Rifle barrels. One of them is an HV barrel and the others are HBR barrels. The tuners are behind the muzzle devices made of bronze. The tuner on the HV rifle weighs 4 oz. I have two other tuners for the three HBR rifles one is 4 oz and it works as it should on the rifle still wearing it. I have another that weighs 3 oz. The other two barrels did not respond favorably to the tuners, either at 3 oz or 4oz. Both of them were easily brought into tune and shoot fine without the tuner (s) but I could not make them shoot well with the tuners installed.

Having read the current thread on the RF forum led me to wonder if I may need more weight on those barels or perhaps less? I have been trying to find tune at the middle of the threaded section on the barrels which is where I found a good reaction with the HV barrel and the one HBR barrel. Weight is very critical on a 10 LB rifle so adding more weight means taking it off somewhere else.

Is anyone willing to opine as to what I may need to do? Thanks in advance.

Pete

 

[David Halblom]

This is not

I have had tuners fitted to 4 of my Benchrest Rifle barrels. One of them is an HV barrel and the others are HBR barrels. The tuners are behind the muzzle devices made of bronze. The tuner on the HV rifle weighs 4 oz. I have two other tuners for the three HBR rifles one is 4 oz and it works as it should on the rifle still wearing it. I have another that weighs 3 oz. The other two barrels did not respond favorably to the tuners, either at 3 oz or 4oz. Both of them were easily brought into tune and shoot fine without the tuner (s) but I could not make them shoot well with the tuners installed.

Having read the current thread on the RF forum led me to wonder if I may need more weight on those barels or perhaps less? I have been trying to find tune at the middle of the threaded section on the barrels which is where I found a good reaction with the HV barrel and the one HBR barrel. Weight is very critical on a 10 LB rifle so adding more weight means taking it off somewhere else.

Is anyone willing to opine as to what I may need to do? Thanks in advance.

Pete

what you may want to hear, but the VH rifle you had in Iowa did not like the tuner. It was tunable W/O the tuner. Why are you worring about it. Shoot it w/o and move ahead. I think you are looking for a crutch w/o there being a sprain.

But I am a Luddite, or so I'm told.

David

 

[Boyd Allen]

I believe that the idea that stiffer is always better, may not always be correct, especially in an application such as yours. On one barrel, that was fitted with one of Jackie's tuners, in order to compensate for the added weight of the tuner, I turned the barrel down so that it had two cylindrical sections about 6.25 inches long, with a sharp step between, and where the larger in diameter transitioned to the original contour at the rear of the barrel. This was done as an economical method of removing the 5 1/4 oz. that the tuner had added. The completed package, tuner, deresonator, and turned down barrel showed a noticeable improvement in average accuracy and bredth tune. I have no hard evidence that the stepped barrel was part of the reason, but I can say that the next tuners that I have fitted will go on barrels with that modification, if only to take off weight, and help restore balance.

 

[Pete Wass]

David,

what you may want to hear, but the VH rifle you had in Iowa did not like the tuner. It was tunable W/O the tuner. Why are you worring about it. Shoot it w/o and move ahead. I think you are looking for a crutch w/o there being a sprain.

But I am a Luddite, or so I'm told.

David

You, somehow, have missed the entire concept of the tuner thing. Tuners are not used as a crutch but simply an easier way to proceed. They give no advantage other than making one's life easier and extending the usable life of a great barrel. Why would you want to deny this from us?

 

[Pete Wass]

It's interesting

I believe that the idea that stiffer is always better, may not always be correct, especially in an application such as yours. On one barrel, that was fitted with one of Jackie's tuners, in order to compensate for the added weight of the tuner, I turned the barrel down so that it had two cylindrical sections about 6.25 inches long, with a sharp step between, and where the larger in diameter transitioned to the original contour at the rear of the barrel. This was done as an economical method of removing the 5 1/4 oz. that the tuner had added. The completed package, tuner, deresonator, and turned down barrel showed a noticeable improvement in average accuracy and bredth tune. I have no hard evidence that the stepped barrel was part of the reason, but I can say that the next tuners that I have fitted will go on barrels with that modification, if only to take off weight, and help restore balance.

how the CF folks seem to have proven that taking metal off a barrel's outside diamater seems not to affect it's accuracy. What number shall we give to the "Never decrease the O.D. of a barrel"? Benchrest Myth?


Boyd, will you post a picture of what you have discribed please?

 

[Boyd Allen]

Tomorrow, when I have time, I will photograph the barrel. The thread for Jackie's tuner is 15/16 by a fine pitch (I forget.) I continued that diameter back till the step up to the original contour became .050 (total diameter difference of .010) I then started a new cut at the larger diameter, and carried it back till the step up to the existing contour was the same as the first one (.050 per side, .010 difference in diameter) Since the barrel had a straight taper, the lengths of the two cylindrical sections is the same. It is a buttoned barrel. In my opinion, a barrel that is properly stress relieved, before contouring, should be able to be cut down and and threaded at the muzzle without problems, as long as you don't go too far. I forget what diameter Gene Beggs' tuners use, but I believe that they are under .9. I should add that this was done as a series of very light cuts, Then we filed, then polished with abrasive paper. The thread was cut a little too tight, and then the barrel was taken off of the lathe and the the threads were polished on a wheel. The result was a very nice fit, snug and smooth.

 

[crb]

Here is my story on bbl turning. I have some Anschutz rimfire bbl blanks that start life as a 1.25" cylinder. I have turned one down to .825 with a 2 or 3" back at the chamber end threaded for a 40x. I use a Pacnor nut on this bbl. It shoots pretty good with tuner.

I have one Annie bbl for this action that I left full dia and shot quite a bit. I recently turned it down to .850 but left the torque shoulder full dia for about 3/4" and then immediately down to the .850 dia with a bit of a radius to the 850.

I then pulled some Eley bullets and used them to slug the bbl so I could properly locate the muzzle at the tightest point in the choked section. What I discovered was a major constriction at the torque shoulder. It actually felt tighter than the choked area. My solution was to turn the torque shoulder and the rest of the tenon to .850 and then fit this bbl to my Hall. Constriction was no longer there after removing the original torque shoulder.

 

[Boyd Allen]

Francis,
A few years ago, Don Neilson tried a tension sleeve on his heavy. In order to allow the T nut that tensioned the sleeve at the muzzle enough room and, I imgine, deal with overall weight, Don turned steps in the barrel, a Hart. Part way throught the days shooting he gave up on the sleeve, pulled it off, and continued. It seemed to me that the barrel performed about as would be expected. This is not to say that I slugged it, or knew anything for sure about the effect the turning had on the ID.

In the case of my barrel, the muzzle diameter was about right as it was, so that the turning did not decrease its size at all. In any case, I think that we need to be careful not to cross apply too heavily from rimfire to center fire. I believe that most makers of match grade button rifled barrels stress relieve after buttoning to prevent bore enlargement that would result from contouring. I suppose that there might be a small amount that happens in spite of this that is taken care of in finish lapping. Anyone know for sure?

 

[Pete Wass]

I wonder if

Here is my story on bbl turning. I have some Anschutz rimfire bbl blanks that start life as a 1.25" cylinder. I have turned one down to .825 with a 2 or 3" back at the chamber end threaded for a 40x. I use a Pacnor nut on this bbl. It shoots pretty good with tuner.

I have one Annie bbl for this action that I left full dia and shot quite a bit. I recently turned it down to .850 but left the torque shoulder full dia for about 3/4" and then immediately down to the .850 dia with a bit of a radius to the 850.

I then pulled some Eley bullets and used them to slug the bbl so I could properly locate the muzzle at the tightest point in the choked section. What I discovered was a major constriction at the torque shoulder. It actually felt tighter than the choked area. My solution was to turn the torque shoulder and the rest of the tenon to .850 and then fit this bbl to my Hall. Constriction was no longer there after removing the original torque shoulder.

the increase in Bore diamater may become more pronounced as the od deminishes in size? Having said that, we are turning our muzzles down to .900 and smaller on our HBR barrels. We should be seeing an increase in I.D. if that be the case, eh? I have neveh slugged a 30 cal barrel so don't know how any of them might feel.

 

[Donald]

My solution to turning the muzzle down is to make up a series, about 3, aluminum sleeves threaded on the outside at about .960 or so by 28 tpi. I just epoxy these sleeves on the end of a barrel, selecting the one that fits the closest. Not that it matters much. Slather on some JB and set it on the end of the barrel. I have two bronze weights with nylon nuts to tighten them that fit the sleeves. One weighes 4 oz the other about 4.5 oz. I guess you could make several of different weights. It takes about 3-5 minutes of heat from a propane torch to loosen the sleeves from the barrels, scrape out the old epoxy and redo. I have had one sleeve on 3 different barrels. Beats the heck out of threading a barrel. And no problems from enlarging the bore. Simple is usually better.

Donald

 

[Dick Grosbier]

You, somehow, have missed the entire concept of the tuner thing. Tuners are not used as a crutch but simply an easier way to proceed. They give no advantage other than making one's life easier and extending the usable life of a great barrel. Why would you want to deny this from us?

Pete,
If it is so much easier a way to proceed obviously it is your imagination that it works better with the tuner removed

 

[mks]

Lower stiffness, lower CG

I have had tuners fitted to 4 of my Benchrest Rifle barrels. One of them is an HV barrel and the others are HBR barrels. The tuners are behind the muzzle devices made of bronze. The tuner on the HV rifle weighs 4 oz. I have two other tuners for the three HBR rifles one is 4 oz and it works as it should on the rifle still wearing it. I have another that weighs 3 oz. The other two barrels did not respond favorably to the tuners, either at 3 oz or 4oz. Both of them were easily brought into tune and shoot fine without the tuner (s) but I could not make them shoot well with the tuners installed.

Having read the current thread on the RF forum led me to wonder if I may need more weight on those barels or perhaps less? I have been trying to find tune at the middle of the threaded section on the barrels which is where I found a good reaction with the HV barrel and the one HBR barrel. Weight is very critical on a 10 LB rifle so adding more weight means taking it off somewhere else.

Is anyone willing to opine as to what I may need to do? Thanks in advance.

Pete

Pete,
Based on VarmintAl's simulations of Esten's 6PPC, short range BR rifles need less barrel and stock stiffness. On Esten's rifle, a 7 oz tuner brought barrel exit times close to the middle (fastest part) of the the favorable rising part of the muzzle projection curve for a stiff 22" barrel. This reduced vertical dramatically, but did not eliminate it. Even faster muzzle rise would further reduce vertical. More tuner weight could be counterproductive, but less barrel and stock stiffness would help. A lower center of gravity for the rifle relative to the bore would also increase the moment that drives muzzle rise. You could lower the CG by using a lighter scope and/or adding weight in the toe of the stock.

The 10# HBR rifle may react very differently. It may already have plenty of moment relative to its lower rotational inertia, so reducing stiffness may work better than lowering CG, and added tuner mass may be more helpful than for an 11.5 or 13.5# rifle.

Cheers,
Keith

 

[Boyd Allen]

picture of stepped barrel

The muzzle was not reduced in diameter (although at this thread diameter, I wouldn't have worried if it had). The thread is 15/16 x 36, 2" long. From the muzzle to the first step is 6 1/4". Paul Mauser http://en.wikipedia.org/wiki/Paul_Mauser is probably smiling somewhere.

 

[Lynn]

Pete
To answer your original question add another weight ring to your existing combination and look at what the vertical does.If it gets larger you have too much weight.If it gets smaller you need even more weight.

If your gun doesn't seem to want to respond to a quarter turn on the tuner the weight is simply wrong!!!!
Lynn aka Waterboy

 

[Pete Wass]

Thanks Boyd

A picture is indeed worh 1000 words.

Appreciate it,

Pete

 

[Pete Wass]

Wellll

Pete,
If it is so much easier a way to proceed obviously it is your imagination that it works better with the tuner removed

I don't think so, that is why I am trying to work through the situation. When they work, they are great, when they don't, one wastes a lot of expensive bullets