Barrel Profiles

[smoothshooter]

I am considering getting a .40 caliber flint rifle with a swamped barrel.
Would the “A” profile be too light and whippy for this bore diameter?
Would the barrel harmonics of a barrel with walls this thin at the waist cause the gun to be more load-sensitive when developing accurate loads?

 

[rchas]

For general hunting or a woods walk shooting contest that barrel will likely shoot straighter than you can hold it. For bench rest "chunk gun competition the heavier the barrel the better. But you have to be a top notch marksmen to notice the difference-- something I am not!

 

[Pete G]

Shooter harmonics has much more effect than barrel harmonics. Just be careful with center lug placement.

 

[Vaino]

My 4th LR was a .36 cal. Bucks County LR w/ a 42" "A" weight bbl and was very accurate. The later BCs used 46" . .50 cal. "B" weight bbls and were also very accurate. The 46" bbls were the reason for the "B" weight. On both bbl lengths, the bbl lugs at the waist were soft soldered on in lieu of using dovetails as w/ the other 3 bbl lugs. The web thickness at the waist is thicker and can accommodate the base of the bbl lug.

Previously shot benchrest w/ 20 lb rifles and 25X 'scopes to lessen the effects of bbl harmonics, but don't think w/ MLers harmonics play a part in the accuracy......Fred

 

[Col. Batguano]

Yes it will be somewhat whippy and bendy. Various manufacturers use different dimensions for the waists of their A weights. So all A weights are not the same. Because an A weight is a thinner overall barrel F-T-F, than a B, C, D weight et. al., a 0.20" barrel wall thickness in an A weight will be bendier than the same thickness with a greater overall F-T-F width. As per above, a .36 in an A weight will have greater wall thickness and be stiffer than a 40 with the same profile. Because of that whippiness, (in your 40) finding the right load for that barrel's individual harmonics will be trickier than for one that is intrinsically stiffer.

Benchrest barrels are relatively short and thick to make them stiffer. A 48" A weight will be whippier in the same caliber than a 42". More mass (and inertia) on the ends to make the oscillations / amplitude greater.