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Estimating BC ....help!

 
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  #1  
Old 02-24-2006, 10:43 AM
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Estimating BC ....help!

Got 50rds of 308 Geco 170gr target ammo for which I’m having trouble finding / estimating a ‘starting point’ BC to put me 'in the Parish' before I launch any downrange tomorrow.

They have good ogives but flat tips….....I’m confused!!
(yes, despite appearances,they are marketed as target bullets).

What would you estimate (I believe they are flat base)??:

Geco in the middle, 165gameking on left (0.404), 165NBT on right (0.475)……the ogives appear similar….just the tips seem different:



The ogive is looks too good to class them with the Sierra Prohunter 170 FN (BC: 0.204).

Some more views of the Geco 170gr tip:






Anyone got anything more edumacated than (0404 + 0.475 + 0.204)/3 = 0.361 ?


Thanks!
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Old 02-24-2006, 11:17 AM
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Re: Estimating BC ....help!

.350?
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Old 02-24-2006, 11:35 AM
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Re: Estimating BC ....help!

kINDA LIKE THESE:

Awesone performance. Too bad Low BC.
[img]/ubbthreads/images/graemlins/crazy.gif[/img]

http://www.northforkbullets.com/308-165.htm
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Old 02-24-2006, 12:50 PM
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Re: Estimating BC ....help!

look at the Speer 30 cal Mag Tips

170 gr has a BC of 0.304
180 gr has a BC 0f 0.352
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Old 02-24-2006, 01:24 PM
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Re: Estimating BC ....help!

Thanks.

That's brought the average down to about 0.34.

-I'll give it a go at that!
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Old 02-24-2006, 04:13 PM
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Re: Estimating BC ....help!

BD, Unfortunately, flat nosed, flat based bullets have a much lower BC. Hopefully, they shoot great to offset their range limitations. Good luck.
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