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Old 01-29-2010, 09:23 AM
VMFn542bob VMFn542bob is offline
Join Date: Oct 2009
Location: Arizona
Posts: 1,066

Originally Posted by americal71 View Post
... Hope this may help!
Sure helps me and confims what I suspected. It makes a lot of sense to shoot through a tunnel. Not only can wind effect be eliminated the entire environment can be controlled inside a tunnel: altitude, humidity, temperature etc, about every variable that can affect the performance of the bullet. With the design of the MANN barrel reducing its effect on the bullet to the maximum extent possible, and the tunnel controlling the environment, the only variable left is the ammunition. That would seem to imply that group width would be then be related to the projectile and group height would be related to the velocity. Because many things can affect velocity that is probably where ammo manufacturers concentrate their attention.
A little trivia: I have read that the performance of the black powder 45-70 GOVT cartridge was so bad that the shape of the bullseye was changed to accept the fact that velocity could not be controlled well enough to shoot at a round bullseye. As a result, the military competition target was changed from a round bullseye to a bullseye that was about twice as high as it was wide.
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