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jfg
03-09-2010, 01:10 AM
Looking for the Ballistic Coefficient of 3 .458 Lyman Bullets:
1. Mold #457132 535 Grain Postell
2. Mold #457658 480 Grain Original Schmittzer
3. Mold #457677 490 Grain Paul Matthews design

Thanks

Southern Son
03-09-2010, 07:21 AM
I think that I remember Mike Venturino did some testing on this in a Magazine Article. I think that I remember that the Postel scored better than the Schmittzer. My memory aint so good, I think? I would love to know the B.C. of the Creedmoore 535 grain boolit I get from my Brooks Mold.

montana_charlie
03-09-2010, 02:13 PM
I understand that the higher the BC number, the better the bullet flies through the air.
Beyond that, the science begins to leave me behind.

However, it is apparently true that a given bullet has a given BC at a given velocity.
If the BC is .500 at 1500fps, you can expect 'the number' to be something else at 1200 fps.
Whether 'the number' gets higher or lower as the velocity goes up (or down) is something I don't have a good grip on.

A few years ago, when the PGT bullet came out, it was claimed to have a 'better BC' than the other commonly used BPCR bullets. You can take those to be the Postell and the Creedmoor without fear of being far wrong.

The claim was based on the fact that it took less elevation to hit with the PGT than it did with the others. Since the PGT is 10 grains heavier than the 540g Creedmoor, and 15 grains heavier than the 535g Postell, perhaps it IS a bit better.

To provide some scale for the o/p to use, the PGT is said to have a BC of .450.
The thing is, I don't know if that is 'the number' when the bullet's moving at 1190 fps...or while it's sitting in the box.

But the shapes of all three bullets are so similar, it leads me to guess that the BC number won't be VERY different as you choose among them.

That might leave a guy wondering if a bullet hovering around the .450 BC number is 'great', 'real good', or 'just acceptable'.
For comparison, the Money bullet (with a pretty radically different nose shape) is said to have a BC of about .570...at 1300 fps

CM

jfg
03-09-2010, 03:38 PM
I received an answer from Lyman today and it is as follows:
Bullet #457132 has a .402 BC.
#457658 has a .372 BC.
Sorry we have not developed a BC for bullet #457677.

Thanks for your input.

jfg