I had seen a product advertised as a de-resonater that is a fat rubber type grommet that is slid on the barrel and placed in a sweet spot, could be a option to try one?
I do know due to the construction of light weight composit wrapped barrels are not only very ridged but dampen the vibrations resulting in pretty decent accuracy.
Having experence with propeller aircraft and am fasinated by metalurgy, I had dealt with crankshaft and propeller balancees, that if not addressed resulted in annoying vibrations causeing all sorts of problems with delicate gyros and causeing oil leaks and working rivets and cracked structure, A device called a Chadwick is used to determine where the inbalance is and corrections to be made, since the composit propeller by ther nature of construction dampen allot of felt vibration in the airframe yes its apples and oranges comparrison but its someting to consider, a rifle is a simple machine that produces vibrations just like any other, on a car a vibration that puts you all over the road at a certain speed with a type of tires gets your attention but a gun folks try to change scopes, crown muzzles, bed the stocks and any manner of tricks to quell this imbalance, its useally fixing the symptom of a problem because by changeing loads and bullet weights changes the vibration thresholds like switching from studded bias ply knobby tires to rain and snow radials at different speeds on the roads.
A fella could have consecutive models of a certain make & model rifle (two savage 110's in 30-06) one may be very tempramental and only shoots one particular set up and the other rifle as mild mannerd when a varity of different round's are tried its not a issue, the technology of produceing a uniform barrel is still a ways off, the barrel steel is rolled useally in one direction and this sets a grain to the metal they broach the rifleing with the grain of the barrel or aginst? like rubbing yer wiskers the wrong way, do they orientate the blanks in the broacher the same all the barrels reamed exact same? broaching the rifleing against the grain may instill stress in the barrel that wouldent occor if done with the grain so any heating will cause these stresses to warp and since the broach traveld aginst the grain its microscopicly rough, even with lapping the bore and cyrogenicly anealing the stress in the barrel from manufacture the damage is still done like petting yer dog the wrong way.
Now you have to wonder yes you can bed the stock and free float the barrel and crown the barrel all contributeing to cutting down the tendency to imbalance the rounds, even adding a BOSS would help
thats why some barrels are inherently accurate and some are lemons that require allot attention like a fickle wife no matter what you do ther not happy and some guy's put up with the ole battle axe and some divorce ther guns at the first gunshow they can find.
barrel blanks roll off the production line they all have the potential to be accurate, not paying attention to metal grain at the boreing process is a start if its done incorectly it leaves a rough bore, then they swap some with and some aginst and they procede to broach then you end up with some that are really bad and some that are passable then a few slip buy that were bored and reamed and broached all the same direction resulting in a inherantly accurate barrel before its even mated to a action, a well squared action and the rest is all gravey.
