TUNNEL REPORT Tues., 10-28-08

G

Gene Beggs

Active member
Being so pleased with the results obtained yesterday morning, I went back to the tunnel yesterday afternoon to continue with the barrel indexing tests. Unfortunately, I had a most unpleasant experience and did not fire a shot.

I have two Stiller drop port actions, both identical with consecutive serial numbers. I had tested the barrel that morning on action number 7005 at the 12:00 and 3:00 o'clock positions. The 12:00 o'clock position shot a .125 group which is good but when the barrel was rotated a quarter turn to the right, the group was a tiny dot. I scribed a mark on the barrel so I could return to that position after checking 6:00 and 9:00 o'clock.

Upon arriving at the tunnel that afternoon, I loosened the barrel, rotated it a quarter turn to the right placing it in the 6:00 o'clock position. Everything was going great until, I got a little carried away when tightening the barrel. When I tried to insert the bolt, it would not go all the way into the action. :eek:

This has happened before so I wasn't concerned; usually the bolt shroud just needs to be slightly repositioned. No such luck. :( This time, I could find no reason why the bolt would not go in the action and began to worry that something was seriously wrong. :eek:

After removing the barrel and taking the action and bolt outside where the light was better, I still could not find where it was binding. I feared I had broken the steel insert loose and twisted it in the action. :(

The light was fading and I decided it would be wise to pack everything up and head for town. I was so afraid I had seriously damaged one of my actions. Bummer, :mad:

All the way home and into the evening, I worried not only about the action but also about how I was going to explain what happened to Jerry Stiller and Curtis Helton. :eek:
I was so depressed. :( But, today I found a silver lining in the cloud.

Early this morning, I went to the tunnel and decided to install the barrel on my second action. I thought it would be interesting to see if the barrel shot best in the same position on a different but identical action.

Today was a classic example of the convenience of the 'Ultralite' aluminum stock. In no more than fifteen minutes, the barrel, stock, trigger and forend were installed on the second action. The barrel was indexed at 6:00 o'clock and I was ready to continue with the tests. Can you imagine how long that would have taken with a conventional glued-in action/stock?

With the barrel in the 6:00 o'clock position on the second action the rifle shot all over the place and was impossible to tune. :mad:

The barrel was then rotated an additional quarter turn and indexed at the 9:00 o'clock position. It shot all over the place. :rolleyes:

I decided to return the barrel to the position in which it shot the best on the first action. This took about five minutes thanks to a scribe mark I had made previously.
After a half turn adjustment of the tuner to remove two bullet holes of vertical, the rifle, once again, shot in a dot! :D I was elated!

Even when installed on two different actions, the barrel shot best in the same clock position. Now that is more than a coincidence; don't you think? :)

It was almost noon so I headed to town for lunch, arriving at the shop about 1:00 pm. In a much better frame of mind and eager to find out what was wrong with my action, I soon discovered the problem.

As it turned out, the problem wasn't serious and I was relieved to find the steel insert had not been disturbed. What had happened was I had raised a burr with the action wrench in the bolt bore immediately behind one of the locking lug abuttments. The fix was easy.

I turned a piece of stock to fit the bore of the action and with a bit of 220 grit lapping compound soon had the tight spot removed. After a thorough clean up and lube, the action is as good as new. :D Sometimes you get lucky; huh? :)

Later,

Gene Beggs
 
Thanks for the update, Gene.

Your experience brings up a good point on changing barrels. I've seen a couple of actions tweaked by the improper use of an action wrench. Fortunately, both just had small raised ditzels that were easily lapped out with a piece of 220 wrapped around a flat piece of hardwood dowel.

One of my pals looks like he's changing a flat tire with an old four way tire iron when he changes barrels. It's painful to watch.......:eek:
 
Indexing works

It works again.

With as much respect as I can convey, Calfee missed on this one. Whether you call it a banana shaped curve, a kink or a wandering path, barrel bores perform best in a specific orientation.

Works in the rimfire world as well. Thank you Mike Ross.
 
Gene,

When all the dust settles, I would be interested in hearing how actual performance correlates with the physical shape of the barrel.

-Spencer
 
Gene, your experience mirrors mine. In all the barrels Mike Ross indexed for me, he never had my action(s), he did them on his own 2013. The before/after improvement once they came back and were mounted on my actions was obvious. Indexing is independent of the individual action. Good to see the confirmation, I'm looking forward to each installment.
 
hulk said:
It works again.

With as much respect as I can convey, Calfee missed on this one. Whether you call it a banana shaped curve, a kink or a wandering path, barrel bores perform best in a specific orientation.

Works in the rimfire world as well. Thank you Mike Ross.
Click to expand...


Mike, thanks for joining the discussion. Stay with us.

For those of you who may not know, Mike is the man that did a lot of experimenting with barrel indexing in rimfires. A nice article by him appeared in Precision Shooting some time ago; I don't remember the year and month.

Mike, I look forward to meeting you. Plan a trip out to West Texas sometime. I would be honored to have you as my guest. :)

Later,

Gene Beggs
 
spencer313 said:
Gene,

When all the dust settles, I would be interested in hearing how actual performance correlates with the physical shape of the barrel.

-Spencer
Click to expand...


Spencer, I will place the barrels in the lathe to see if the curve, irregularity or whatever correlates to the index mark on the barrel where it shot the best.

Later,

Gene Beggs
 
Now, Gene-

With the problems solved you may have excess spare time on your hands. On bbl indexing [thank you for all of your effort AND sharing your results!] have you put an indicator about the center of the bbl [outside] while between centers? Was there any correlation of high/low reading to new found sweet spot index mark? Would have to check several bbls to reach any conclusion I suppose.
I would almost swear the last bbl I checked was ground between centers. I thought my indicator was defunct.

The light at the other end of the tunnel may NOT be a train headed our way!

Steve Moore
 
Gene,
This is solid gold.

Stephen,

Its not the outside of the barrel that is being indexed, but the major direction of the curve of the bore. (I'm pretty sure.)

Boyd
 
Last edited:
Boyd-

I think Spencer and I are trying [I am verry trying at times] to find out if there is any relation of curvature of the bore whether elytpical, parabollic, or just plain old zig-zaged. Which may not have any bearing on the "new found sweet spot index mark".

Just trying to figure all of the angles or CURVES!

Steve Moore
 
Stephen B Moore said:
With the problems solved you may have excess spare time on your hands. On bbl indexing [thank you for all of your effort AND sharing your results!] have you put an indicator about the center of the bbl [outside] while between centers? Was there any correlation of high/low reading to new found sweet spot index mark? Would have to check several bbls to reach any conclusion I suppose.
I would almost swear the last bbl I checked was ground between centers. I thought my indicator was defunct.

The light at the other end of the tunnel may NOT be a train headed our way!

Steve Moore
Click to expand...


Steve, when I first began experimenting with indexing, I built a jig to check the balance of the barrel, theorizing that if the OD or ID wandered off center, the heavy side would come to rest at the bottom and boy did it ever!

The jig supported the barrel on ball bearings between centers and it was dramatic how unbalanced most barrels were. This is something I will investigate further now that I have the means to check the barrels in all positions and return to a specific position without turning metal off the tenon shoulder. If you alter the barrel in any way, you really don't have the same barrel.

The barrels being turned out today by the top makers are consistently much straighter than those of ten years ago.

This has certainly been interesting; huh :cool:

Later,

Gene Beggs
 
Sorry

Gene,

Sorry for the confusion but I am not Mike Ross. I was simply thanking him for his work with rimfire barrels.
 
Gene you said...

Steve, when I first began experimenting with indexing, I built a jig to check the balance of the barrel, theorizing that if the OD or ID wandered off center, the heavy side would come to rest at the bottom and boy did it ever!

It would be nice if you could keep track of the balance and the indexing. See if there is a corelation between the two. Would be nice if one could just spin a barrel between centers, pick the low or high or whatever point and set it up that way. BTW, does anyone remember the month/year that Mike Moss' article appeared in PS. I have looked and looked but can't find it but I do remember reading it. Seems it was some time last year. Keep up the good work.............Donald
 
First thing,Gene should be praised for his experiments into the barrel indexing area. This is for the most part, an uncharted area. Mike Ross and I have been doing some testing & were all but told that we were full of it, because some people were not ready to believe our results. I think that MIke used an Anschutz clamp style action. I have an action I made for my own testing. It's aluminum, it has a 1" bore that accepts bushing, that fits the barrel tenion, whatever size. My action uses 3 screws to tighten around the barrel & the action goes onto my Railgun top. You can shoot a 10 shot group & you do not even need a scope so 10 shot groups will give a real good agg from a barrel in a certain position. Rotate the barrel & compare the results. Do this 3 to 5 times & the results will be certain -- good or bad, you have an accurate way of testing. Do this with 20 or more barrels & you really start to see what is going on. There are some that think that the position of the bore has a bearing on the results, not so. Every barrel has its own mind & no 2 are the same. Some will benefit from being indexed, while others will only show small improvements. This is because they are already hummer barrels. First off, a barrel has to be prepped before chambering & one needs to know how straight the bore actually is. If you can detect an amount of curvature that is enough so that you can point it in a certain direction, you should not install this barrel. They need to be straight. I am not talking about the small amounts of runout that occurs from the drills wandering. I sold one of my Lathes to BIll Snyder of Tucson Arizona & when he came in to pick it up, I showed him how prep a barrel. It was a Broughton 5c 6 mm barrel. This barrel was straight & we trued both ends. There is no way for anyone to point this barrel in any direction, other than straight in line with the centerline of the action. This is where it belongs. If it would of had a curvature, it would of been returned for replacement. The law of nature tells you that there are no perfect anythings in this world & barrels aren't even close, so common sense will tell you that to rotate a barrel,will make it better or worse. I have never made a setup for Centerfire testing, although I did ponder on it for a while & decided against it for reasons of not enough hours in the day anymore. But I will be interested in Gene's results. Thanks Gene, BILL
 
Bill

The vast majority of Kriegers that I chamber are about as straight as you could expect within the parameters of deep hole drilling.

Many of the spots that we see as run out in reality are only a couple of thousanths. Some, you can't visually see any runnout what so ever.

That is why the method that Gene is using is the only valid way to "index" a barrel for optimum performance. But even at that, will the barrel still suffer from the same tuning maladies that many shooters seem to never solve??

Personally, the overall hassle of doing all of this might not even be worth the effort, since you can utilize a tuner to optimize the barrel, that is, if you are a shooter who actually uses a tuner. Add to the fact that in order to acsertain any improvement, you need to insure that other factors, such as tune and conditions, don't skew the results. Afterall, not everybody has a tunnel.

All of this sounds great when sitting at a keyboard. But, much of the excitement and luster might fade when a shooter is hit with the realities of the real world.........jackie
 
I shoot "Crude" rifles BUT - - -

I can see a big difference between those barrels that shoot well and those that have to be coaxed to shoot "Pretty Well". The barrels that shoot well, shoot well most of the time and better in conditions vs the ones that are just on the ragged edge of being in tune because they are "Ragged" to begin with.

Many of us don't have the resources to chamber a number of barrels and choose the best one ('s) to use; wish we did but the fact remains we don't if we want to have any money left to compete with. If indexing will make some of these barrels shoot well, so mush the better for the Po Boys in the game, assuming the "Kits" won't cost more than a new barrel. :confused:
 
jackie schmidt said:
The vast majority of Kriegers that I chamber are about as straight as you could expect within the parameters of deep hole drilling.

Many of the spots that we see as run out in reality are only a couple of thousanths. Some, you can't visually see any runnout what so ever.

That is why the method that Gene is using is the only valid way to "index" a barrel for optimum performance. But even at that, will the barrel still suffer from the same tuning maladies that many shooters seem to never solve??

Personally, the overall hassle of doing all of this might not even be worth the effort, since you can utilize a tuner to optimize the barrel, that is, if you are a shooter who actually uses a tuner. Add to the fact that in order to acsertain any improvement, you need to insure that other factors, such as tune and conditions, don't skew the results. Afterall, not everybody has a tunnel.

All of this sounds great when sitting at a keyboard. But, much of the excitement and luster might fade when a shooter is hit with the realities of the real world.........jackie
Click to expand...

Jackie, the one barrel that I would really like to see re-indexed is the barrel that you used in the first tournament of this year.

If I remember correctly, while breaking it in and setting it up for this years first tournament you thought it was as good as any barrel you had ever put on your sporter, but when you actually began the competition it lasted about 6 matches and you finally removed it from your gun because it was firing occasional flippers from very small groups, and the proven replacement barrel that you installed confirmed that the problem was with the original new barrel, as groups went back to being consistent and competitive.

Do you still have that barrel and have you done anymore work on it to eliminate the flippers?

Would this be a good candidate for re-indexing?................Don
 
Don

That barrel is standing in the corner some where, I think has "Piece of Cr-p" written on it.

You make a good point. Something to look at.......jackie
 
Barrel Indexing

For some time now I have been indexing my barrels with a straight section of the muzzle in a verticle plane, usally looking at 6:00 o:clock. If I understand correctly the function of a tuner is to remove verticle, it seems to me that the muzzle should be in that plane. Seems to work well for me.

Sam Duke
 
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