Boyd,All this conjecture and opinion, and so little reference to testing. Here is a piece about a clever friend of mine who has done some actual testing in a tunnel.
http://bulletin.accurateshooter.com/2008/10/beggs-devises-indexing-system-for-centerfire-barrels/
Sunnen honeing only does honeing I never have seen a cutter. Years back they mite of made boring bars .
Back to the barrels the last 2 I have seen off of true bore the run out wa .008 and the other was..002 in 31 " first time I have ever seen a barrel that straight let alone two in a row.. When you put them up to a light and rotated the barrel the light rings never moved.
For ever barrel were straighten by using light rings. Does the company I got the barrel from use sunnen honeing .I never ask . But two in a row Seems strange to me. But I do know a couple of barrel makers have got them. They could be one. Larry
My earlier post in this thread explain my experience with indexing smallbore barrels. The indexing of a barrel to the 12 clock and 6 o'clock positions resulted in timing a barrel for the best possible harmonics and improved group sizes. From your post it sounds like you are under the impression that timing a barrel at the 12 o'clock position is for a purpose other than improving the harmonics of the barrel. Do I understand you correctly? Are you of the impression that timing a barrel to improve harmonics such as we see with smallbore applications and timing a high-powered rifle barrel to a 12 o'clock position are for two separate reasons?Boyd,
Correct me if I'm wrong but the orginal post was on indexing the barrel run out from the way they are chambering their barrels (Gordy's Method) and are indexing their run out at 12 oclock.
Beggs and the rim fire guys are indexing the barrels for the best tune or harmonics.
I have no skin in the game and both methods work and I beleive the indexing Beggs did could improve some barrels.
"Sunnen honeing only does honeing I never have seen a cutter."
Go to the Sunnen web site or goggle Sunnen PLB 100 line boring attachment and or Sunnen PLB 1200 cam boring attachment and reevaluate your position on what Sunnen does or doesn't
The reason I want mine timed is to take advantage of gravity .My earlier post in this thread explain my experience with indexing smallbore barrels. The indexing of a barrel to the 12 clock and 6 o'clock positions resulted in timing a barrel for the best possible harmonics and improved group sizes. From your post it sounds like you are under the impression that timing a barrel at the 12 o'clock position is for a purpose other than improving the harmonics of the barrel. Do I understand you correctly? Are you of the impression that timing a barrel to improve harmonics such as we see with smallbore applications and timing a high-powered rifle barrel to a 12 o'clock position are for two separate reasons?
Thanks,
Trevor Hengehold
That is my thinking. Time at 12 seems to me would be best . LarryI believe that the whole timing thing for CF barrels came about as a result of the practice of indicating a barrel in, through the headstock, in such a manner so that the chamber end of the bore is coaxial with the rotational CL of the spindle. In order to arrive at this alignment, the position of the muzzle end can be significantly off off of spindle CL. At that point, the question arises as to how that offset should be clocked relative to the action, and the page, that I published a link to, (and the link within that page that pointed to similar work done with rimfire rifles) was included to point out that evidently that clocking makes a difference as far as accuracy is concerned.
It is my understanding that competitive barrels have been chambered by all three common methods, two through the headstock, and the third using a steady rest. I think that this is good news for those who have lathe issues that make it difficult or impossible to use one or more of these methods. A short bed could make using a steadyrest impossible for a given barrel length, just as a long headstock might make it difficult to indicate both ends of short barrel, or even secure it at the outboard end of the headstock.
Even if a barrel is indicated so that both of its ends are on spindle CL, if there is a curve between those points, the question might arise as to how that curve should be clocked relative to the action, even though the OD of the barrel, and the bore at both ends are centered.
When we pressurize a water hose that has a closed valve at its fee end, it "tries" to straighten out. I think that to a much lesser degree curved bores may do the same thing as they are fired, with the inertia and mass of the bullet causing the straightening pressure. It is my guess that the motion induced by this mechanism that causes differences in group sizes when barrels are clocked in various orientations to their actions, but this is just a guess.
My earlier post in this thread explain my experience with indexing smallbore barrels. The indexing of a barrel to the 12 clock and 6 o'clock positions resulted in timing a barrel for the best possible harmonics and improved group sizes. From your post it sounds like you are under the impression that timing a barrel at the 12 o'clock position is for a purpose other than improving the harmonics of the barrel. Do I understand you correctly? Are you of the impression that timing a barrel to improve harmonics such as we see with smallbore applications and timing a high-powered rifle barrel to a 12 o'clock position are for two separate reasons?
Thanks,
Trevor Hengehold
Boyd Allen describe it in detail. Read the reason he said ( probable .) LarryThe original poster and as Larry stated are timing barrels in the 12 position for long range shooting as mentioned in Gordy's video due to the curve of the bore.
I tried the indexing or timing on a center fire rifle once. Built a rail test fixture with a barrel block so I could rotate the action at different timing points and shot them at 100 yards. The groups moved around on paper as I rotated it and they did shoot better in one plane. I ran into a catch when I did it though.... So one plane did shoot better than the rest but I then tried a different load and the plan moved to a new best.....so what caused this, was it because the barrel was showing me better harmonics or was I tuning the gun to the load since I was rotating the action around and causing it to rotate mass and act as a tuner? Beggs had the right way of doing it since he was not rotating his action on his center fire.
I gave up on the project as there was too many variables that I could not control.
Dallas
All this conjecture and opinion, and so little reference to testing. Here is a piece about a clever friend of mine who has done some actual testing in a tunnel.
http://bulletin.accurateshooter.com/2008/10/beggs-devises-indexing-system-for-centerfire-barrels/
The original poster and as Larry stated are timing barrels in the 12 position for long range shooting as mentioned in Gordy's video due to the curve of the bore.
I tried the indexing or timing on a center fire rifle once. Built a rail test fixture with a barrel block so I could rotate the action at different timing points and shot them at 100 yards. The groups moved around on paper as I rotated it and they did shoot better in one plane. I ran into a catch when I did it though.... So one plane did shoot better than the rest but I then tried a different load and the plan moved to a new best.....so what caused this, was it because the barrel was showing me better harmonics or was I tuning the gun to the load since I was rotating the action around and causing it to rotate mass and act as a tuner? Beggs had the right way of doing it since he was not rotating his action on his center fire.
I gave up on the project as there was too many variables that I could not control.
Dallas
What barrel makers do you know of that utilize a honing machine?
Now you you said who they were I will tell both the barrels were Bartlein. They were the straightest barrel by far. With that in mind could it be the Sunnen honeing or or just Luck ! LarryBartlein, Pac-Nor, Benchmark, Lilja
Neither the honing or luck. Their drilling process & tooling, most likely.Now you you said who they were I will tell both the barrels were Bartlein. They were the straightest barrel by far. With that in mind could it be the Sunnen honeing or or just Luck ! Larry
I never have seen anything about the drilling process being changed that hasn't changed in years. Guess I have good luck. LarryNeither the honing or luck. Their drilling process & tooling, most likely.
Seems strange to me the barrels were 5 months apart . In 5 months I got the same drill and it still was sharp.You need to get the honing making a barrel straight out of your mind. Everybody does not use the old 30s and 40s Pratt and Whitney machines and they ain't bad. Proper setup, correctly sharpened and pointed drills, and a good pressure feed of cutting oil. I love straight barrel, but have shot some that the bore wasn't too straight and they shot lights out.
