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Old October 11, 2012, 09:30 PM   #8
Senior Member
Join Date: December 24, 2010
Location: Canada
Posts: 382
Recoil is a function of momentum which tends to make heavier rounds recoil more heavily in a given caliber.
Momentum is actually a product of mass and speed, not mass alone. In other words, relative momentum is equivalent to the measurement of IPSC power factor. A 115gr bullet traveling 1130 fps has the same momentum as a 147gr bullet traveling about 880 fps. Both make minor power factor and can be used for production division. But which have the lightest "felt" recoil?

It takes MUCH less powder in order to move a heavier bullet the same power factor as a lighter bullet. Less power = less gas expansion = less energy. Remember that not all that energy is contributing to the momentum of that bullet. This is why I have never witnessed anyone (that is not a newbie) in production division who shoots anything lighter than a 147gr bullet. I shoot one heavier than that.

Contrast this to those who shoot 9mm open division with major PF. They want as much energy as possible in the form of huge volumes of gasses that will make their compensator work. So their trick is to use the lightest bullet allowed and stuff the most powder they can in a case while making major. While a great deal of that energy isn't transferred to the bullet, it doesn't end up going out the end of the barrel, but instead exhausts from the ports to compensate for the gun's tendency to flip up during recoil.
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