Heavy 6ppc Barrel Question

[R.Morehouse]

Is there any performance issue with going to a 27" HV barrel chambered in the mentioned 6ppc? Rifle balance and weight are not a concern......Has anyone seen any chrono increases using a 6ppc in a longer barrel.....Thanks for your input.

Regards
Rick

 

[JEFFPPC]

Probably more difference between one's ears than on target. For years all my 6brx barrels were 26in. Then I tried 27 and 28. Saw no practical gain. Went back to 26 in. Within a .1 of Varget tuned all at 2990 with 107s.

 

[Eric Leonard]

My last 2 were 25” and I got 3410 with 28.35 LT32 and Barts Avengers. I been thinking about goin longer also.

 

[gunsandgunsmithing]

I'm not after speed when I load but I do like a bbl that "talks" to me in regard to tune. A less stiff bbl generally does so a bit better and a little more length goes a pretty long way in it becoming less stiff, fast. It also moves the balance point forward pretty fast, too though. I don't think there is a "magical" bbl length for a rifle.

 

[BoydAllen]

I'm not after speed when I load but I do like a bbl that "talks" to me in regard to tune. A less stiff bbl generally does so a bit better and a little more length goes a pretty long way in it becoming less stiff, fast. It also moves the balance point forward pretty fast, too though. I don't think there is a "magical" bbl length for a rifle.

For a very long time, for benchrest, barrel stiffness has been viewed as a virtue. I have come to question this. My current working premise is that as long as a barrel is heavy enough to deal with the thermal load without accuracy being affected during normal use, it is probably heavy enough. The potentially expensive part would be to try to determine how light a barrel can be without loosing accuracy just because of its profile. I can say one thing that is clear. If we view a free floated barrel as a cantilevered beam, and take a look at the formula for calculating deflection under load, when a barrel is shortened, it becomes a lot stiffer.

Cantilever Beam Calculations: Formulas, Loads & Deflections

Maximum reaction forces, deflections and moments - single and uniform loads.

www.engineeringtoolbox.com

My point is that if a barrel was stiff enough before shortening we can re-contour it to remove more weight and bring its shortened stiffness (deflection under a given load) down to what it was when longer. If tuning a load involves timing the exit of the bullet at the muzzle to a certain point in the motion of the muzzle's vibration, it seems to me that raising the frequency of the barrels vibration would make timing to muzzle more critical, which would seem to make close control of velocity more critical. Years ago, I asked Harold Vaugn whether his work had shown him that barrel stiffness and weight were desirable characteristics for accuracy. He told me that weight is, but stiffness may not be as clear an advantage, or words to that effect. For those that are not familiar, he wrote a very interesting book about some very interesting experiments that he had done relating to factors that affect accuracy of a rifle. It is titled, Rifle Accuracy Facts.

 

[gunsandgunsmithing]

For a very long time, for benchrest, barrel stiffness has been viewed as a virtue. I have come to question this. My current working premise is that as long as a barrel is heavy enough to deal with the thermal load without accuracy being affected during normal use, it is probably heavy enough. The potentially expensive part would be to try to determine how light a barrel can be without loosing accuracy just because of its profile. I can say one thing that is clear. If we view a free floated barrel as a cantilevered beam, and take a look at the formula for calculating deflection under load, when a barrel is shortened, it becomes a lot stiffer.

Cantilever Beam Calculations: Formulas, Loads & Deflections

Maximum reaction forces, deflections and moments - single and uniform loads.

www.engineeringtoolbox.com

My point is that if a barrel was stiff enough before shortening we can re-contour it to remove more weight and bring its shortened stiffness (deflection under a given load) down to what it was when longer. If tuning a load involves timing the exit of the bullet at the muzzle to a certain point in the motion of the muzzle's vibration, it seems to me that raising the frequency of the barrels vibration would make timing to muzzle more critical, which would seem to make close control of velocity more critical. Years ago, I asked Harold Vaugn whether his work had shown him that barrel stiffness and weight were desirable characteristics for accuracy. He told me that weight is, but stiffness may not be as clear an advantage, or words to that effect. For those that are not familiar, he wrote a very interesting book about some very interesting experiments that he had done relating to factors that affect accuracy of a rifle. It is titled, Rifle Accuracy Facts.

Agreed. Good book, too!