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Old September 3, 2012, 03:54 PM   #24
Bart B.
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Join Date: February 15, 2009
Posts: 8,927
Here's two barrels fit to receivers bolted in a stock; both 30 caliber. The bore diameter of .306 inch was used to equal what a typical 4-groove area of .308" groove diameter would be (.0736 square inch). My software only uses one diameter for the bore. Use the profile below for dimensions listed:



First barrel, typical 24" sporter rifle:

bore diameter = 0.306 inch
breech diameter A = 1.25 inch
reinforce large diameter B = 1.25 inch
reinforce small diameter C = 0.8 inch
muzzle diameter D = 0.6 inch
reinforce length AB = 2.75 inch
reinforce taper length BC = 3.25 inch
main taper length CD = 18 inch
total length = 24 inches
total weight = 3.191 lb

Second barrel, typical 30" Palma rifle:
bore diameter = 0.306 inch
breech diameter A = 1.25 inch
reinforce large diameter B = 1.25 inch
reinforce small diameter C = 0.92 inch
muzzle diameter D = 0.82 inch
reinforce length AB = 2.5 inch
reinforce taper length BC = 2.5 inch
main taper length CD = 25 inch
total length = 30 inches
total weight = 5.095 lb

Which one's stiffer and by how much?

One of them vibrates at about 71.5 cycles per second and that's about the frequency where the greatest amount of bore axis angular spread happens at the muzzle as it whips in the vertical axis for that barrel's contour. It goes through one cycle in about 14 milliseconds. Bullets take about 3 milliseconds to go from case mouth to out the muzzle.

Last edited by Bart B.; September 3, 2012 at 06:59 PM.
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