Sorry for the newb question, but I haven't been able to find this anywhere. The Shooter app I have is asking for the bullet length. I'm assuming that is the length of the bullet itself, excluding the case. Can someone give me that value for 168 gr SMK?
- Thread starter jferguso
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Hard questions to answer cause even in the same lot.. They vary in length.
1.215"
It's also listed in the Shooter Bullet Library for both the advertised and Litz ballistic coefficient.
Litz has bullet diagrams in the back of his Applied Ballistics book. Berger lists their bullet dimensions in their reloading manual. Litz was compiling a length list, check his website.
Inter lot and lot to lot variations in length are completely insignificant for the way Shooter is going to use that dimension.
Check out the bullet library in Shooter. Ammo, +, From Bullet Library
Are you loading these yourself or are they factory ammo? If you know the velocity of the load (or an approximation per published data) and the BC of the bullet, you should not have to create a new bullet profile.
More than likely the program is using the greenhill formula whereby length of bullet is of more importance than weight.
The copy on my phone gives numbers that look like the Miller formula actually.
Given the stability threshold is somewhere between 1.3 and 1.5, and the 168 is ~1.8 with a 1:12 twist, you just don't need to know the bullet length to thousandths of an inch.
You do need to have a number entered though so the ap will give you spin drift. Which is another approximation that doesn't need extreme accuracy on the bullet length estimate.
Given the stability threshold is somewhere between 1.3 and 1.5, and the 168 is ~1.8 with a 1:12 twist, you just don't need to know the bullet length to thousandths of an inch.
You do need to have a number entered though so the ap will give you spin drift. Which is another approximation that doesn't need extreme accuracy on the bullet length estimate.
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