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  #1  
Old 05-29-2018, 12:53 PM
Mark527vARMINT Mark527vARMINT is offline
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Default Ballistic coefficiant

How do you work out what the ballistic coefficient is on a swagged bullet ?, i have some hand swagged .172 30grn flat based match , im trying to work out some info for strelok pro .
Any body have any berger 30grn in .172 ?

Thank you Mark
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Old 05-29-2018, 01:36 PM
Harold M Harold M is offline
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Measure the velocity at two distances from the muzzle, something like 100 yds apart. It requires two chronographs. Use a ballistic program to see what BC produces the measured velocity drop.

Harold
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Old 05-29-2018, 04:28 PM
Mark527vARMINT Mark527vARMINT is offline
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Thank you i have 2 chronographs ill give it ago.
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Old 05-29-2018, 08:10 PM
Mark527vARMINT Mark527vARMINT is offline
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Hi all hopefully i got it sorted as i phoned Berger and spoke to Bob Blaines who helped no end with data and other advice.

Thanks for looking

Mark
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  #5  
Old 05-30-2018, 12:10 AM
squirrel_slayer squirrel_slayer is offline
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you can also setup a target at say 300 yards zero the rifle at 100 and chrono the load then measure the POI vs POA then use your strelok to reverse engineer the BC.

Ie. rifle zero'd @ 100yd @xyz ft/sec with .xxx bc= drop @ 300

just keep changing the bc till it matches up then verify by stretching it to 400-500. fine tune if needed remember to find the centerline of the verticle dispertion of the group don't worry about what the wind is doing.
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