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Old 04-02-2009 | 07:03 PM
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gleason.chapman
Nontypical Buck
 
Joined: Dec 2005
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Default RE: Velocity, ft-lbs accuracy

ORIGINAL: jaw3

Is there a source that recommends velocity for a given weight/type bullet.
If I load a 330 gr Harvester sabot with 90 gr 777 I get about 1550 fps.
If I load a 280 gr Harvester sabot with 90 gr 777 I get about 1650 fps. I'm just starting this quest for
velocity, ft-lbs accuracy quest, but wonder if the increase charge is worth the extra vel or should the
defining fact be when the group starts to open?
Any thoughts?
Regards,
You need to know the ballistic coefficient of the bullet. Usually on the manufacturer's web site or "Google is your best friend". Example lets do 330g Harvester on their web site, here it is:

http://www.harvestermuzzleloading.com/index.php?view=article&catid=3%3Asaber-tooth&id=3%3Asaber-tooth-load-data&option=com_content&Itemid=4

You can see by the load data that 10g of powder is getting you only 50 more fps, approximately. The
Saber Tooth is shaped like a XTP, so I think it is going to have a ballistic Coefficient like a 330g XTP

http://www.nfa.ca/nfafiles/cfjarchive/ballistics/bcchart.doc#C45

which is .180 for the 300g XTP, so drop the values .180, 330 and 1550 in a balistic program and sight in at 145 yards for about a 3" high at 100.

Here is a Screencast on how to run a ballistics program:

http://screencast.com/t/NGC51UoF2Sg

Chap
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