Quote:
Originally Posted by Scalce
I am just curious why I always see references to 300 Whisper rounds at 1050 fps but you guys seem to be wanting to get it around 1000 fps to keep it from going transonic.
Interesting
I think the 1000 fps makes more sense anyway unless there is some severe increase in drop or lack of accuracy but I am not sure 50 fps makes that much of a difference at that point.
Anybody have any real world drop charts for the various velocities?
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In my opinion 1050fps is an ideal speed that everyone would like to hit. It allows the max energy while still remaining subsonic. The reason everyone seems to be loading to 1000fps is to allow for the variation that occurs and the temperature changes as well. If I load up 500rds in the winter when I'm not shooting a lot I'd like that ammo to work out in the summer when I do. The increase in outside temp sometimes increases the velocity of the ammo into the transonic range. Some powders are pretty temp sensitive (H110-W296) while others are not (N110). I've seen H110 loaded at 1000fps during the winter spit out the same slug at 1150 during the hot summer. Needless to say we don't use H110 for anything other than load and shoot days. Others may have other reasons but that seems to be the consensus among those I've spoken with.
Hope that gives some helpful reasoning.
As for real world drop charts I'd suggest the JBM Ballistics website and their calculators. I've had great results using their trajectory calculator for figuring drops using my actual data from tests.
http://www.jbmballistics.com/
frank
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