NEWS FROM THE TUNNEL, Barrel Indexing

[Gene Beggs]

Gene, you never did answer as to how this "needs indexing" barrel was aligned for chambering. And, I strongly disagree that only one in twenty barrels are Top-5 competitive. Tony keeps more than that and he is probably the most demanding shooter I know......except a certain shooter named Jack.

Jerry, sorry about the delay in answering your question but I have been mulling it over in my mind and have concluded that we are talking about two different things.

You're talking about how to set the barrel up for chambering in the lathe; I'm talking about taking an existing rifle, one that I may have never seen before, and re-indexing it to see if one clock position shoots better than the others.

You're right; I was probably a bit overly critical about the percentage of competitive barrels that would be found among twenty. I guess I was thinking more in terms of what Tony Boyer calls, "Hummers." They don't come along very often. What I'm trying to do is increase those odds to as close to 100 % as possible.

And you're right again; the quality of barrels being made today is far better than that of twenty years ago.

Later,

Gene Beggs

 

[AVanGorder]

Barrel nut, floating bolt head and shims.

Adrian "The Savage King" Van Gorder

Hey man, we may fight over that "savage king" title,,,,,,,,,,,,

the wind is my friend,,,,

DD

Double D, Fights over, I win, got the "Buckle" to prove it!

Adrian

 

[GS Arizona]

Over the course of 100 years or so of the development of the modern target rifle, improvements in bullets, barrels and bedding have been the focus of most of our efforts and rightly so - they produce results. Largely this has focused on improved design, manufacturing and fitting. In the course of this, we (the core group of accuracy minded shooters) have been exposed to countless gadgets and elixirs that promise improved accuracy but really don't deliver.

In my 38 years of fiddling with rifles (relatively short compared to many other forum members) I have found exactly one thing outside of the traditional approach that has produced reliable, consistent and repeatable (over many rifles) improvement in accuracy - barrel indexing. I would suggest that anyone who needs to get up to speed on the whys and wherefores of the process re-read Mike Ross' article in Precision Shooting (February 2006). If you absolutely can't get a copy, let me know, I edited that article and can send you a copy.

In the strictest sense, indexing is still part of "bullets, barrels and bedding" so we haven't really strayed too far. I will leave all discussions of the inner curvature of barrels to others, but I can absolutely confirm that rimfire barrels will shoot best at their favored index point. I can't see why centerfire barrels should be any different in that regard. Mike Ross' work with respect to indexing was groundbreaking, though he didn't see it that way. He pointed out that Franklin Mann did similar work 100 years earlier. However, Mann did not connect the dots, Ross did.

Gene, I've read this whole thread twice and will probably do so again, simply because I'm very happy to see indexing getting it's due in the hands of someone with the ability, facility and credibility to bring it to a wider audience. Mike tried, but was pilloried by Calfee in a manner that left many of us with a jaundiced view of Calfee's approach to testing - science was notably absent. I hope you succeed in showing that barrels, like the earth itself, have curves that can be used to our advantage. Gravity, by the way, is the force at work on vibrating barrels that almost everyone ignores.

 

[HuskerP7M8]

Everyone who endorses barrel indexing seems to get hammered so I’ll stand in line and await the blow, but I happen to agree with Gene, German, and Mike Ross on the importance of indexing.

For those of you who still don’t believe indexing is a factor in accuracy, I suggest you do your own testing or find someone who will. I don’t care how carefully you measure or what methods you use to determine if a barrel is straight….you will find the majority of barrels will disperse shots around a center point as they are rotated even if you think they are straight by your chosen measurements. I don’t know if one or more curves in the bore caused by the very nature of deep hole drilling is responsible for this phenomenon, but it is present nevertheless.

After you have determined this, I would think common sense has to convince you that an often dramatic change in POI during barrel rotation has to have some affect on accuracy for better or worse. It would affect the initial muzzle movement as the rifle recoils and the way the barrel vibrates when the force of gravity is factored in.

Landy

 

[Pete Wass]

I have always wondered - - -

Why certain things like barrels that don't shoot well enough, even tho we paid a big price for them and there was every expectation that they would shoot well, has become an accepted situation among both shooters and gunsmiths. We all realize that some barrels, even those from the same lot of metal shoot better than others.

Personally I am glad to see folks like Gene jump in and TRY to do something about the situation; something that is DIFFERENT. I also wonder why there are those who want to immediately Pillaty folks like Gene whenever they announce breakthroughs. It seems that they see Snake Oil Salesmen everywhere!

Most folks who TINKER don't have the facilities to do dramatic things like Gene seems to do and most of those who do have the facilities don't seem to THINK much about how to improve on what we have. Just an observation.

Pete

 

[Gene Beggs]

Over the course of 100 years or so of the development of the modern target rifle, improvements in bullets, barrels and bedding have been the focus of most of our efforts and rightly so - they produce results. Largely this has focused on improved design, manufacturing and fitting. In the course of this, we (the core group of accuracy minded shooters) have been exposed to countless gadgets and elixirs that promise improved accuracy but really don't deliver.

In my 38 years of fiddling with rifles (relatively short compared to many other forum members) I have found exactly one thing outside of the traditional approach that has produced reliable, consistent and repeatable (over many rifles) improvement in accuracy - barrel indexing. I would suggest that anyone who needs to get up to speed on the whys and wherefores of the process re-read Mike Ross' article in Precision Shooting (I'll edit in the issue month tonight, maybe Jan. 2007). If you absolutely can't get a copy, let me know, I edited that article and can send you a copy.

In the strictest sense, indexing is still part of "bullets, barrels and bedding" so we haven't really strayed too far. I will leave all discussions of the inner curvature of barrels to others, but I can absolutely confirm that rimfire barrels will shoot best at their favored index point. I can't see why centerfire barrels should be any different in that regard. Mike Ross' work with respect to indexing was groundbreaking, though he didn't see it that way. He pointed out that Franklin Mann did similar work 100 years earlier. However, Mann did not connect the dots, Ross did.

Gene, I've read this whole thread twice and will probably do so again, simply because I'm very happy to see indexing getting it's due in the hands of someone with the ability, facility and credibility to bring it to a wider audience. Mike tried, but was pilloried by Calfee in a manner that left many of us with a jaundiced view of Calfee's approach to testing - science was notably absent. I hope you succeed in showing that barrels, like the earth itself, have curves that can be used to our advantage. Gravity, by the way, is the force at work on vibrating barrels that almost everyone ignores.

Right on German!! Very well stated and very well written. I wish I had your way with words.

Later,

Gene Beggs

 

[Gene Beggs]

Why certain things like barrels that don't shoot well enough, even tho we paid a big price for them and there was every expectation that they would shoot well, has become an accepted situation among both shooters and gunsmiths. We all realize that some barrels, even those from the same lot of metal shoot better than others.

Personally I am glad to see folks like Gene jump in and TRY to do something about the situation; something that is DIFFERENT. I also wonder why there are those who want to immediately Pillaty folks like Gene whenever they announce breakthroughs. It seems that they see Snake Oil Salesmen everywhere!

Most folks who TINKER don't have the facilities to do dramatic things like Gene seems to do and most of those who do have the facilities don't seem to THINK much about how to improve on what we have. Just an observation.

Pete

Pete, thanks for the encouraging words. I am looking forward to your visit to the tunnel.

Later,

Gene Beggs

 

[Gene Beggs]

Everyone who endorses barrel indexing seems to get hammered so I’ll stand in line and await the blow, but I happen to agree with Gene, German, and Mike Ross on the importance of indexing.

For those of you who still don’t believe indexing is a factor in accuracy, I suggest you do your own testing or find someone who will. I don’t care how carefully you measure or what methods you use to determine if a barrel is straight….you will find the majority of barrels will disperse shots around a center point as they are rotated even if you think they are straight by your chosen measurements. I don’t know if one or more curves in the bore caused by the very nature of deep hole drilling is responsible for this phenomenon, but it is present nevertheless.

After you have determined this, I would think common sense has to convince you that an often dramatic change in POI during barrel rotation has to have some affect on accuracy for better or worse. It would affect the initial muzzle movement as the rifle recoils and the way the barrel vibrates when the force of gravity is factored in.

Landy

Hi Landy

Thanks for joining the discussion, I appreciate your input. Lot's of exciting things are happening; huh?

Later,

Gene Beggs

 

[Big Al]

I know one thing for sure after reading this thread. If Gene comes up with a system that allows for easy barrel indexing, the shooting world will beat a path to his door.

 

[mwezell]

Another way to attach the barrel and allow easy indexing, might be to set it up similar to the way an AR15 is. Use a nut on the barrel to pull a shoulder up to the action face. Just a thought. It doesn't seem like it would be hard to make an adaptor to accomplish this.--Mike Ezell

 

[Vibe]

Gene. I know you covered part of this a few pages back on this thread....But I came in late.
It really doesn't matter which threads you pick, 18tpi/28tpi, 16tpi/26tpi, or even 14/24....Each of these represent a 10tpi differential and will adjust identically.
If I were doing it I probably would have gone with a smaller differential, but in one way or another anything other than a 0 differential will work...eventually. Up to and including a 20tpi/1.25mm(20.32tpi) which is only a 0.32tpi differential.
Truth be told, you could even mix and match left handed and right handed threads in some cases. Not that there could be a benefit to that...It's just doable and would work.

 

[Gene Beggs]

Another way to attach the barrel and allow easy indexing, might be to set it up similar to the way an AR15 is. Use a nut on the barrel to pull a shoulder up to the action face. Just a thought. It doesn't seem like it would be hard to make an adaptor to accomplish this.--Mike Ezell

Mike, I considered this approach during R & D but my dream was to come up with something that would work on most all existing actions; something that would be inexpensive, easy to install, easy to adjust, safe and foolproof. I believe I have, at last, achieved my dream. The barrel indexer, once installed, is completely hidden from view and no modifications to the action are necessary.

Stay tuned; kits should be available soon. Of course, it must be installed by a trained gunsmith. I can arrange for installation.

Later,

Gene Beggs

 

[Chisolm]

Gene,
I just want to say thank you for your efforts in advancing rifle accuracy, and openly posting your findings.
I for one did not believe Calfee's findings in the PS article about indexing, not that I had done any scientific testing, it just makes sence to me that it would have an effect.

James

 

[Gene Beggs]

Gene. I know you covered part of this a few pages back on this thread....But I came in late.
It really doesn't matter which threads you pick, 18tpi/28tpi, 16tpi/26tpi, or even 14/24....Each of these represent a 10tpi differential and will adjust identically.
If I were doing it I probably would have gone with a smaller differential, but in one way or another anything other than a 0 differential will work...eventually. Up to and including a 20tpi/1.25mm(20.32tpi) which is only a 0.32tpi differential.
Truth be told, you could even mix and match left handed and right handed threads in some cases. Not that there could be a benefit to that...It's just doable and would work.

Thanks for the information. This thread has created a lot of good feedback.

During the past couple of days, much progress has been made and a significant improvement has been added to the barrel indexing system.

The differential thread, internal bushing design remains unchanged with the exception of 24 tpi now being used in place of 28 tpi for the barrel tenon and bushing ID. The procedure for making adjustments is much improved; I think you'll be impressed.

With the original prototype, the adjustable bushing was installed in the receiver and secured with a set screw to prevent it from moving as the barrel was tightened making it necessary to completely remove the barrel each time an adjustment was made.

With the new procedure, you never remove the barrel and you do not have to consider the thread differential and place the bushing in a specific position. You simply loosen the barrel, visually place it in the desired position and with a specially designed tool, go in from the breach end of the action and snug up the bushing. The barrel is then torqued up tight with a barrel vise and rear-entry action wrench. Pretty slick; huh?

Later,

Gene Beggs

 

[Gene Beggs]

Gene,
I just want to say thank you for your efforts in advancing rifle accuracy, and openly posting your findings.
I for one did not believe Calfee's findings in the PS article about indexing, not that I had done any scientific testing, it just makes sense to me that it would have an effect.

James

Thank you James, I appreciate the kind words. I assure you, it has been a labor of love. Sharing what I learn with others who love accurate rifles makes it even more rewarding.

Later

Gene Beggs

 

[Vibe]

With the new procedure, you never remove the barrel and you do not have to consider the thread differential and place the bushing in a specific position. You simply loosen the barrel, visually place it in the desired position and with a specially designed tool, go in from the breach end of the action and snug up the bushing. The barrel is then torqued up tight with a barrel vise and rear-entry action wrench. Pretty slick; huh?

Later,

Gene Beggs

LOL. Yeah. I thought it was. But I thought the tool design a bit fragile when I did it. I was working with a very thin walled bushing though, and much smaller differentials, in the design I was working on. Oddly enough, the main thrust of what I was working on at the time was a way to vary the headspace of a rimfire without changing the barrel clock position.

 

[Gene Beggs]

LOL. Yeah. I thought it was. But I thought the tool design a bit fragile when I did it. I was working with a very thin walled bushing though, and much smaller differentials, in the design I was working on. Oddly enough, the main thrust of what I was working on at the time was a way to vary the headspace of a rimfire without changing the barrel clock position.

How 'bout that? Well, like they say, "There's nothing new under the sun." Most anything we come up with has been used before in some way by others. I got the idea for my tuning collar design and the way it operates from the chuck on a little table top lathe.

The tool I built to go in the rear of the action and position the bushing is quite strong and sturdy. It is all aluminum except for the hardened 5/32 square key that engages the notches in the rear of the bushing. The main shaft is .500 6061 T-6 aluminum rod with a knurled aluminum handle somewhat like the tools we use to swab out chambers.

Later,

Gene Beggs

It's surprising what you can discover if you keep your eyes and ears open; eh?

Later,

Gene Beggs

 

[Gene Beggs]

Gene
In a nut shell what can be expected from this bushing? Say I have a barrel that is shooting 0.230 only occasionaly and mostly around 0.280
Do I install the bushing and try the barrel at say 11 positions 30 degrees apart looking for an occasional 0.120 group or what?
Also once you find it likes say 120 degrees of rotation.Do you then mark the barrel and move the shoulder back so it indexes at that point or leave the bushing in there until the barrel is shot out?
Lynn

Lynn, the bushing becomes a permanent part of the installation. Once the best position is located, it should not be changed. If the barrel must be removed, you should mark it in some way so it can be reinstalled in exactly the same position.

I test at only eight positions, 12:00, 1;30, 3:00 and so on although you could use twelve or whatever.

Later,

Gene Beggs

 

[AVanGorder]

Pictures

Gene,

Do you have some pictures? I have a wild and vivid imagination, want to make sure I'm on the same track.

Adrian

 

[Stephen B Moore]

Lynn-

If You took the bushing out, you would have to cut off the bbl tenon and rethread to 18 tpi, shorter bbl, different harmonics, maby having to start all over again! My thought is shoot it till it doesn't then start with a new bbl, same bushing set up, then make "time" for a "nooner" with the new bbl.[clock it or index to 12 o'clock].
All this to do before the next shoot!
Steve Moore