We have all grown up hearing opinions on whether a rifle barrel should be shorter or longer. The Kentucky long rifle that was brandied as the ultimate accurate shooter in the days of black powder certainly carried the perception through. As far as velocity is concerned the argument holds true but not so on accuracy.
In an article on Accurrateshooter .com make some interesting observation on the issue of barrel length.
"Going from 20" to 24" can increase velocities up to 160fps (40fps per added inch), depending on the rifling. After that, expect another 25-30fps extra velocity for each added inch up to about 28?. Beyond that, you"ll probably get a little extra speed, especially with 6BR Improved cases. We recently completed a barrel velocity test using a rail-gun. A Krieger 6mm barrel chambered for a standard 6BR was cut down from 33" to 28" in one-inch increments. The Average Velocity at 33" was 40 fps higher than at 28". .... So arguably, 26" is long enough, at least for the Improved cases. For maximum speed, 30" is a useful limit, but remember that this adds weight to the gun and you"ll be sacrificing barrel stiffness."
On the question if a shorter barrel is more accurate
"As a general rule, the answer is yes. A shorter barrel will be stiffer, pound for pound, since you can run a thicker contour (diameter) with the same weight. As you increase diameter, barrel rigidity rises to the 4th power of the increase. But if you lengthen a barrel, stiffness declines in proportion to the cube of the length. So a barrel that is just a few inches longer and a bit thinner can be half as rigid as a 20" max contour barrel (More details). The added stiffness of fat 20-22" BR barrels raises barrel harmonic frequency to the point that barrel vibration becomes a non-issue (provided the bedded action is rigid as well)."Â�
These observations are of course for Benchrest shooting over shorter distances. After a 150 meters the velocity of the longer barrel will indeed contribute to the accuracy with its increased velocity.
Read the whole article on more barrel issues here.
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