Barrel contours for tuners on 10.5# PPCs

B

Boyd Allen

Active member
Since we are having such productive discussions of tuners, I thought that I might ask what fellows who are using them have done about barrel contour, and the resultant weight, and stiffness. It seems to me that there is a relationship between barrel stiffness and how much a tuner must weigh for it to be effective. This last year Lou Murdica used a double disk, behind the muzzle (barely) tuner on his rail gun. It looked like the bag gun version on steriods, and he used it effectively to tune vertical out of his groups as the temperature went up. On a LV/Sporter that is to be shot free, there is always the issue of rifle balance, which is probably more critical when more traditional fiberglass and carbon fiber stock designs are used, that have shorter, and possibly less rigid forends than wood and carbon fiber stocks. Scopes have gotten heavier, and the rifle weight limit has not changed. In Varmint Al's computer simulations, one thing that was done to change where, in the muzzle's rise the bullets cleared the muzzle, was to weaken the barrel slightly in the center by reducing its diameter, creating a mild "hinge". Back in the day, Browning found that their BOSS tuners, worked better with actions bedded in hard rubber. All of this at right angles to the traditional stiffer is better approach to benchrest barreled action design. I know that trying to follow the rimfire model of barrel contour, and tuner has been tried, and did not work, but do you think that barrel contour, weight and relative stiffness need more study, given relation between barrel stiffness and tuner weight? What contour, length and weight are your barrels that are fitted with tuners?
 
First thing, if you start with the normal LV setup, stock, action LCS or March scope, LV taper barrel, you will have to loose some weight somewhere to be able to install a tuner with sufficient weight that will keep the barrel in tune. You could go to an 18" barrel and get by without turning the barrel but at most ranges setting up with an 18" barrel is a B****.

There are several turned profiles that will work. I never tried the reverse taper (Calfee) style since by the time I got the barrel down to about 4# 2 oz or so I was tired of looking at it.

The easiest to do was the Peter Paul Mauser step since you are only working on a short section at a time.

For your ease of mind, always slug the barrel before turning, then slug it afterwords. If the bore changed you screwed up bigtime (like using a dull edge, K-land or radiused carbide.

 
Wade at Shilen has the program for Shelly's taper to allow for a 5-6oz tuner. They did a couple of reverse tapers for me also.
 
I gave mine to Jay Lynn as I had not been able to shoot for 2 years. He played with it a little and said it shot well. Pat Byrne has the other and hasn't chambered it.
I guess that the jury is still out.
 
Interesting...
Do you have any numbers on the contour? This is the first that I have heard of a reverse taper on CF, except what rifle silhouette shooters and some old muzzle loaders have used.
 
My 10.5 lb. LV/SP use a HBR taper barrel (21" & 4lb, 14 oz.) and threaded for a Beggs tuner. The muzzle dia. at this length is .855. Stan Ware did all the barrel work and threaded it for the tuner. With Gene's tuners being threaded for the LV barrels, Stan and I debated different methods of doing this but settled on a significant behind the muzzle location. Stan ran the cutter in until the barrel taper picked up the thread and and made the threaded portion 1.250 long. The gun is well balanced and not sensitive to bag placement. This is a proven good gun which has won and finished well in quite a few 100's, 200's and 100/200 Grands in registered IBS Score competition.

I haven't been using the tuner on the gun in competition for several reasons, but testing has shown that it certainly does change the tune. Recently, I added a specific durometer B.A.R.T. (Big Azz Rubber Thing) ;) to see if it would dampen the harmonics and/or change the 'width' of the tune. Seems to have done both, though the conditions were sporty....

Good shootin'. -Al

tuner.jpg


P.S. Boyd, I know your post specified 10.5 #PPC's......but not being real smart I figured .30's might also apply?
 
Last edited:
Al,
Good pic. How about one of your B.A.R.T. in place, on the barrel. As I have written before, when I used Jackie's early model (lighter no rubber or brass) tuner in conjunction with the Deresonator, it seemed to me that the node was wider and the rifle shot better, and closer to the wind (bullet impacts seemed to be more in agreement with what the flags were showing) than it had BT (before tunner). Jerry, I agree that the Mauser method makes the most sense for lightening a barrel for tuner installation. Mine was done with a sharp HHS cutter, with many light cuts, so as not to heat things up. The final finish was produced with an abrasive belt. I think that this kept the barrel cooler. For the barrel that was fitted with Jackie's tuner, we turned it to the major diameter of the 15/16" threads back about 6 1/4" to a point where the step up to the original contour amounted to a difference in diameter of .1". From that point, another cylinder was turned at the +.1" diameter, to the point that the step up to the original contour was .1, about the same length as the front cylindrical section. The reduction in barrel weight was around 5 1/2 oz.
Boyd
 
If you look closely at the pic, you'll see B.A.R.T. ;) sandwiched between the tuner rings.

Normally, Gene's rings butt against each other...metal to metal. -Al
 
Contour

None of my barrels for my Sporter weigh more than 76 ounces at 21 1/2 inches, that gives me weight for my 5 ounce tuner.

I use a standard Krieger LV profile, I simply cut all but 1 inch of the "straight" from thye big end, and enough from the muzzle end to make a 21 1/2 inch barrel.

This has worked great for quite a few years. Granted, I have not been able to shoot much in the past year because of work, (lots of it), but my Rifles still shoot up to snuff, if I can remember which end the bullet comes out of.........jackie
 
The Hunter profile works well. I very timidly ordered one back in the 1990s for a VFS build with a barrel block, after reading Dan Lilja's article. It shot very good. Then I found out that R.G. Robinett used them pretty much exclusively on his rifles, and not just for Hunter class rifles. With Al Nyhus using them successfully as well, I'd say they're pretty good candidates as an alternative to Jackie's method (which obviously works, too).
 
Last year at Luther, Darrel Lokar had a rifle with a HV barrel on it that he had fluted until it matched LV weight. The flutes looked more like boards on a paddle wheel steamer. Never saw flutes so deep and wide. I said something like aren't you afraid to shoot that thing with flutes that deep. He said something like he got under the bench the first time he fired it. But he said it was almost a stiff as a HV but stiffer than a LV. Gun and Darrel shot like a house afire. Don't remember it he was using a tuner on the end.

On another subject has anyone tried a tuner about mid way on a barrel? Seems as thoght I read and article that was pretty old about this subject. No it was not the Simms unit. Just wondering. Nothing else to do.

Donald
 
Donald said:
On another subject has anyone tried a tuner about mid way on a barrel? Seems as thoght I read and article that was pretty old about this subject. No it was not the Simms unit. Just wondering. Nothing else to do.

Donald
Click to expand...

By mid-barrel tuner, do you mean something with clicks, or something like Al Nyhus' BART -- I've tried a Henrich device on a CF, it does seem to have an effect. More testing needed before using the word "helps."
 
You must log in or register to reply here.
Back
Top