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Old February 24, 2009, 12:38 PM   #1
tpcollins
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Bullet depth-include/exclude boat tail chamfer?

I'm getting ready to reload for the first time and will be seating 70gr Nosler BT into .243. For my first rounds I want to seat .243" of bullet but my Noslers have a boat tail chamfer on the back that's roughly .060" wide.

Would I want to seat just .243" or .303" to allow for the chamfer? Thanks.
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Old February 24, 2009, 03:16 PM   #2
Unclenick
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You want to seat the bottom edge of the bullet bearing surface to the one caliber depth, if you are trying to follow the old rule of thumb that there is usually a good seating depth accuracy spot there? See this thread. I posted an illustration of bullet nomenclature there in post #20. I've put it up on this forum before, too, but I've forgotten where? You'll want to adjust that depth until you find minimum group size, then adjust the powder charge to tune it in still tighter.
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Old February 24, 2009, 05:21 PM   #3
30Cal
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"One caliber's depth" is something you would eyeball to ensure you've got enough neck tension to keep the bullet from falling out (assuming your case necks are correctly sized). You don't need to measure it down to three significant digits. 0.050" isn't going to matter really from that respect.

Your loading manual should give you an overall length for the bullet you've chosen. I wouldn't go blindly seating bullets blindly past that length unless you know for sure they aren't going to get stuffed into the rifling when you chamber the cartridge. Bullets seated too long (into the rifling) can give you excessive pressure issues.

Before you go out on your own for seating depth, you'll need to either do some measuring with the appropriate gages, or you'll need to do some trial and error to find where the lands are for that particular bullet (stuff cartridge into the chamber--if it doesn't fall out from gravity alone, it's too long).
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