Although I don't shoot rimfire, I found the Gun of the Week article that is currently featured on the main page of this site,click on the picture) outstanding. Beyond a well done job of chronicling the story of the development of one rifle, it offers excellent data on barrel clocking,complete with pictures) and offers convincing argument, based on well done testing, that Calfee may be wrong about the importance of firing pin placement. It is well worth your time. Good job!
Great article!
- Thread starter BoydAllen
- Start date
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Thanks Boyd.
It's a touchy subject because Bill Calfee's rifles have achieved spectacular accuracy without barrel indexing. But that doesn't necessarily rule out the potential gains to be had by indexing, particularly in prone/position rifles which really aren't suitable for massive, heavy tuners--such tuners would make the guns much harder to hold.
I think we have to see indexing as just one more option in a set of things that can be done to enhance accuracy. I would never say you can't have a superbly accurate rifle without indexing the barrel first. There are plenty of rimfires that can shoot Ones and even Zeros with non-indexed barrels.
But if I had an Anschutz 2013 action with a cone breach, I think it would be crazy not to experiment with indexing. There's a big potential upside and virtually no downside,except time invested).
As German Salazar noted to me recently, indexing can help make a good barrel shoot better, but this is just part of the equation:
"Improvements are cumulative and as the system gets better, each successive change may make less of an absolute change, but the percentage improvements can still be found. Indexing removes a lot of the "noise" in a barrel and lets all your other tuning mechanisms give cleaner results,ammo selection, torque, tuner, etc.)."
With indexing, German adds: "The effect is so big that it's clear with any decent ammo,Wolf) and with the barrel free of any tuner. Better ammo and a tuner will NOT change the index point, they will just keep on shrinking groups like always."
It's a touchy subject because Bill Calfee's rifles have achieved spectacular accuracy without barrel indexing. But that doesn't necessarily rule out the potential gains to be had by indexing, particularly in prone/position rifles which really aren't suitable for massive, heavy tuners--such tuners would make the guns much harder to hold.
I think we have to see indexing as just one more option in a set of things that can be done to enhance accuracy. I would never say you can't have a superbly accurate rifle without indexing the barrel first. There are plenty of rimfires that can shoot Ones and even Zeros with non-indexed barrels.
But if I had an Anschutz 2013 action with a cone breach, I think it would be crazy not to experiment with indexing. There's a big potential upside and virtually no downside,except time invested).
As German Salazar noted to me recently, indexing can help make a good barrel shoot better, but this is just part of the equation:
"Improvements are cumulative and as the system gets better, each successive change may make less of an absolute change, but the percentage improvements can still be found. Indexing removes a lot of the "noise" in a barrel and lets all your other tuning mechanisms give cleaner results,ammo selection, torque, tuner, etc.)."
With indexing, German adds: "The effect is so big that it's clear with any decent ammo,Wolf) and with the barrel free of any tuner. Better ammo and a tuner will NOT change the index point, they will just keep on shrinking groups like always."
Do we know that Bill doesn't index his barrels?
A number of years ago I had a conversation with John Illum, then a silhouette pistol and bolt action manufacturer. He told me that he indexed the curve in barrels to 12 o'clock so that windage would not have to be put into sight changes for different yardages at pistol silhouette matches. One way that he economized was to buy untapered match grade,big name)rifle blanks, and cut them in half,contouring both halves) to make barrels for his bolt action silhouette pistols. He probably knows more than anyone about how far off center the bores of match grade barrels are in their centers. I think that an indexing test on a centerfire barrel would be interesting. Have you heard of one?
Boyd
A number of years ago I had a conversation with John Illum, then a silhouette pistol and bolt action manufacturer. He told me that he indexed the curve in barrels to 12 o'clock so that windage would not have to be put into sight changes for different yardages at pistol silhouette matches. One way that he economized was to buy untapered match grade,big name)rifle blanks, and cut them in half,contouring both halves) to make barrels for his bolt action silhouette pistols. He probably knows more than anyone about how far off center the bores of match grade barrels are in their centers. I think that an indexing test on a centerfire barrel would be interesting. Have you heard of one?
Boyd
Forum Boss
Administrator
Boyd,
German Salazar has contacted a fellow with a 6PPC Rail gun who is interested in doing a centerfire test. If it employs a barrel block clamp it should be quick and easy. I suspect the observable POI shift will be much less because: 1) shorter barrel with less curve probably; 2) much faster velocity.
German Salazar has contacted a fellow with a 6PPC Rail gun who is interested in doing a centerfire test. If it employs a barrel block clamp it should be quick and easy. I suspect the observable POI shift will be much less because: 1) shorter barrel with less curve probably; 2) much faster velocity.
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