You Gotta See This

Well it's good for me to learn something when I read these threads. I never knew that some barrels were vibrating in the threads. It's a wonder that anything could help in that case. Thanks for sharing!!
 
There was a very interesting article in this months Precision Shooting by Bill Calfee. He is the premier 22 LR BR smith of all times. He wrote about picking winning barrels by slugging the bores, finding the right end to chamber and where to put the crown based on tightness. He wants the muzzle to be at the tight end regardless of how the blank came in marked. He also wrote about barrel tuners. Destroyed a lot of myths and confirmed some facts I had heard before.

For example fluting a barrel after rifling will change the internal bore dimensions. Well documented by him and Tim North of Broughton barrels. Yet how many "smiths" will flute a barrel and have no idea they just opened up the bore?

He is writing another article this month on how to pick centerfire barrels and tuners for them. Tuners for centerfire are going to become the "thing" to fine tune barrel harmonics for extreme accuracy.

A dampener is a gimmick, you either use an adjustable tuner or use a load development method like the "ladder/audette method" 12/24/02 in Bullets, Ballistics on this site to fine tune the load.

Personal opinion is a "loose barrel action" is an anomoly otherwise they would vibrate loose. The machining might be poor quality but that is across the board in most factory guns and has zero affect on the barrel harmonics. Most factory barrels are too rough and not accurate enough to do real good harmonic balancing by load development.

BH
 
Fiftydriver
I missed their attempt or demonstration of "tuning" via position with it. I stand corrected if thats their claim. I realise that anything touching a gun will effect it, and where it touches will seem better or worse. But for this device, if it works, and wherever it is finally placed, the "tune" is still going to vary with timing changes in load. IAW you will always be able to go in and out of tune, regardless of where the device is positioned. I wouldn't think you would reposition the device like a true tuner, specifically to compensate for timing issues/load variations. Again, just trying to express another perspective. I see it mor as a damper than tuner.
BountyHunter
I agree with you 100%. And I hope Bill is right. But if he is, I hope most that he is convincing enough to sway the masses. Within the past 7yrs I have tried to persuade every big barrelmaker on the planet to make me a few taper bored barrels. Not one could or would. Most big barrelmakers claim exact(.00001)consistancy from end to end, and yet they mark muzzle end as if "tightest". Pure BS.
When challenged, I found that most had no means of measuring internal dimensions of a rifled, lapped, and contoured bore. And most did not account for or even acknowledge bore growth in contouring.
It's no wonder barrel performance is abstract. Their manufacturing and machining is left to the abstract.
In my view a better barrel could be made and known to be better without shooting it, than todays barrels. It should be UNDER bored and rifled AFTER contouring, then extrude honed with the barrel -at operating temperature, hottest at the breech, coolest at the muzzle, until dimensions are perfect. Thats right -perfect.
 
Bounty hunter, your statement on threads having no affect on harmonics was confusing. In Haorld Vaughn's Rifle Accuracy Facts, they showed a distinct link between the threads and barrel vibration. What do you base your statement on?
 
257Speed

You must have a different book by Harold Vaugn than I do. Chapter 4, page 42 "In the course of this investigation we will find that moments that cause barrel vibration result from the recoil force acting on the recoil lug, and from the bolt thrust acting on both the bolt lugs with uneven engagement and from forces generated by the cartridge case acting on the receiver that is structurally assymetrical."

No where in the "Accuracy Facts" book does Harold Vaughn discuss "loose barrel threads and impact on harmonics". He discusses each one of the other areas in detail.

I think you are confusing chapter 6, which discusses "Barrel, Receiver Threaded Joint Motion, which discusses variables that impact barrel grouping related to oil on threads, teflon tape, rosin and other items that effect the "preload on the barrel". However that has zero to do with the harmonics.

BH
 
Warning! This thread is more than 20 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.
Top