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Posted: 1/3/2009 12:12:43 PM EDT
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I'm putting a muzzle break on my two praire dog rigs. One is a RRA Varmint A4 with a 24" barrel in .223 and the other is a Savage bolt gun in 22-250.
Will I need to adjust my loads or am I good to go? Thanks in advance. |
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The undamped natural frequency of a cantilever beam with a mass on the free end varies with the fourth power of the length of the beam from the (center of mass of the) weight to the supported end.
That means that moving a weight on the end of a barrel by very small increments causes large changes in the basic motion of the barrel. For example, let's say the original length when the weight is installed is 22 inches, then the muzzle device is moved out 0.2 inches. The change in the first mode of the natural frequency is (22/22.2)^4 = 0.96; the natural frequency is reduced to 96% of the starting point. The physical problem is more complicated because a rifle barrel is not an undamped cantilever freely vibrating, but this is an important starting point to understanding the effect of adding muzzle weights. You'll also find that long slender barrels will be easier to tune with a muzzle device, and short stubby (stiff) barrels will not respond without massive weights; the stiffer the barrel, the more mass required at the muzzle is required to get useful changes. The ideal situation with a tuned barrel is to get the barrel to vibrate with a node exactly at the exit of the bore. Back to the original question, whether your loads need to adjusted depends on the weight of the brakes and the barrel contour, and whether the rifles have enough inherent accuracy so that you can tell the difference. I would be interested to hear the results of any load experimentation you try. |
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