Velocity/transonic question

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  • Last Post 24 March 2019
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Pentz posted this 24 March 2019

Can anyone with appropriate software or data provide an approximation of muzzle velocity necessary for a 206 gr cast 30 caliber bullet to avoid going transonic circa 1100 fps at 300 yards?  Elevation 1200 ft, temp. circa 55 degrees, from a 5-groove 1917 30/06.  Maybe one day I'll get one of them Labradar thangs...

Thanks in advance....

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frnkeore posted this 24 March 2019

Mike,

You will have to supply the BC of the bullet, to do it accurately.

Frank

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joeb33050 posted this 24 March 2019

If BC = .2, MV = 2000 FPS, THEN 300 YD V = 1141 FPS

IF BC = .25, MV = 1800 FPS, THEN 300 YD V = 1148 FPS

IF BC = .3, MV = 1700 FPS, THEN 300 YD V = 1167 FPS

IF BC = .35, MV = 1600, FPS, THEN 300 YD V = 1163 FPS

IF BC = .4, MV = 1550 FPS, THEN 300 YD V = 1134 FPS

ACCORDING TO http://www.shooterscalculator.com/

A 30 CAL 206 GR BULLET HAS BC IN THE VICINITY OF .3, I'D LOOK FOR MV 1800 FPS OR HIGHER.

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Pentz posted this 24 March 2019

Frank. Length 1.21, nose .302, front band .310, read band .3105. It groups MOA at 100/200 with 17.5 2400. Basic Thanks, Joe for the reply!.

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frnkeore posted this 24 March 2019

The shape and length of the ogive, as well as the SD, is what will determine the BC. If it's a NOE design, it will have a calculated BC, if Lyman, it may have a tested BC, If custom, I'd have to have a example to calculate it.

Joe's info should get you close.

Frank

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Pentz posted this 24 March 2019

Thanks Frank. It is a copy of the 311195SP cut to my bore and throat by a friend. Joe's data will get me close enough. Mike

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