Test it in the area of 7 inches from the muzzle.   
If the flat harmonic's noise is not there, start at the top of a vertical with a brass hammer

I can't even imagine there'd be a difference ... and as a certain starship pilot was known to have said ... 'I can imagine quite a bit'.

The only condition I could see making an accuracy difference would be in the case of a poorly stress relieved, button rifled barrel being turned down and the bore opening up.

I had one do that, and it didn't seem to effect accuracy. But that was a high pressure cartridge shooting jacketed bullets. And I really didn't shoot it very well at 1k with irons anyway

Sine?

Personally I hate the look of a half round barrel and just pure logic says a octagon form is harder to bend than a round one.

Long barrels "drift" across the target slower especially in OH which can result in a bullet being in or out of the black. Shooters saw this a lot with service rifle competition using M1's and M14's. The heavier weight on the front end (similar to a longer barrel) of the M1 would result in bullets in the black vs out of the black with an M14 when comparing the sight picture when the round broke. he sights (muzzle) just drifted slower across the target.

Of course longer barrels also allow longer sight radius's and contribute to more precision in aiming...

Thanks to all for your observations.

I've seen everything from 'Rail Gun' profiles (short fat) to longer thinner (to make weight) barrels.

One of my goals in this project is to keep the project in the same genre as the rifles designed in 1885, like the Hi Wall. So going short and fat or pencil thin is not something I'm interested in.

I spoke with Stan at Douglas barrels this morning and asked him about profiles, his response was that opinions are all over the map when it comes to barrel Whip.

More research needed....

Again thanks for your observations.

Bob
rgchristensen wrote on Mar 31^st, 2022 at 9:49pm:

SAG

Not so much Round or Octagon but an article about length and harmonics in "Precision Shooting". A Quality Company, started trimming down the length and measuring groups.  Found a spot where the groups tightened up.  So maybe leave the Barrel long, do the Tapping Test to find the Dead Spot and trim the length bit by bit.  More Coffee... David

SchwartzStock wrote on Apr 1^st, 2022 at 8:24am:



Now you're into something I know something about. My experience is mostly with bullseye, or standard, pistol shooting, you know, with the turning targets at 25 yards, stationary targets at 50 yards, .45 ACP and .22 LR. However, the following applies equally to rifles, to include long range BPCR. Here is the dichotomy- longer sight radii are inherently more accurate, but they accentuate any visible shortcomings, therefore distracting the shooter, thereby lessening scores. Shorter sight radii mask visible errors, thereby helping shooters who are newbies, tired or shaky, or have recently had a soda, a cigarette, or are just inherently more shaky. Muzzle weights help some, but are really marginal. I never saw more than a few with additional weights on their .22 pistols. Here is my firm conclusion after many years of competition(excluding bench rest), rifle or pistol, if marginal aspects like sight radius, and barrel length, and muzzle weight are occupying your attention, you very much need to concentrate on fundamentals- breath control, trigger control, posture, recovery after the shot, and the most important, sight alignment. This applies to the M1 vs. M14 sight pictures also.