Barrel harmonics and heavy barrels

[West Calamus]

Just finishing up on build in 300 win mag with a 26 inch #6 or lightweight target with microbrake on end. So barrel weighs above 5 1/2 lbs. About 50 rds. down the pipe. I dropped the build back into the reworked barrel channel on original wood stock. Bedded 3/4 inch in front of recoil lug then floated out to about 3/4 inch from end of stock. Was fixing to remove the contact point at end of barrel so rifle would be free floated all the way. Then I started thinking!!! Do these heavy barrels have harmonics like lighter barrels or are the barrels so stiff that they have negligible harmonics or do I need to bed barrel at end of the stock for support? Appreciate all helpful advice from the experienced and more knowledgeable. THX

 

[West Calamus]

A few terms to look at so there's no confusion:

Barrel whip/flex
Barrel harmonics
Heat dissipation

As long as the barrel whip takes place consistently then you will have accuracy. A shorter barrel has less of a fulcrum so it would in theory have less whip. Same goes for heavier and shorter barrel.

Barrel harmonics is more of a reverberation/vibration though there's other things that go into it depending what literature you follow. It refers more to the when the bullet is traveling there being a crest, a trough, and a normal barrel position and POI is relevant to where the bullet leaves based on the timing of those positions and accuracy being how consistent it does. Reloaders tend to try to find way to manipulate this timing. You'll still have harmonics in a heavy barrel, though I can't say for sure if heavy barrels have less harmonics 100% of the time more than lighter barrels. We would need to look at everything, all else being equal.

Heavier barrels are more so used to control heat. Shooting over bore cartridges or a sustained volley of fire, a heavier barrel allows this before internal conditions start to effect the trajectory, without going to much into case temp and so forth. The extra material acts like a heat s

one would think a Barrel of this contour would have no barrel whip issue's.

 

[dfanonymous]

one would think a Barrel of this contour would have no barrel whip issue's.

I never said it does or doesn't. However it's not a matter of it it does or doesn't, because they all do to one degree or another.

As far as "issues," again, as long as it's consistent, there will be some form of accuracy excluding other considerations.

 

[woodnut]

Old school said to bed light and free float heavies. But, each rifle is a law unto it's own. I just witnessed a 1 3/4 " steel pipe, about 24" long, put into a CNC machine to show flex. You would not believe it if you didn't see it, but with very little finger pressure it would flex almost a 1/2" ! Yes, ALL barrels will flex. The fun part is to get the muzzle to be in the same "spot" as the bullets leave it. True also, that little barrels will flex more than heavier ones. The trick is to get the harmonics tuned to where the the muzzle is in the same "spot" each time the bullet leaves it. I would first try free floating. If you aren't happy there, then you can bed it. Some smiths even take the bedding in steps,too. Bed just 2" into barrel channel, check that. Then more. Probably will show up quickly which way works best for you rifle. Just be sure to check it with the same conditions each time. I am not sure what to use, but you can temporarily bed it with, say clay or some other solid but removable "bedding". Might want to run that by someone more experienced than me.

 

[tobnpr]

Clarification?
You first mentioned 50 rounds when the action was in a different stock.
How was that set up, and how did it shoot??

Trying to figure out if you're trying to solve a "problem" (didn't shoot well with the barrel floated in the original stock) ?

 

[bigngreen]

That's not that big of a barrel, no need to over think it, bed the recoil lug back and float the barrel.