New Army "Caliber Configuration Study"

[stanc]

Obviously, I want to put the 65G in the best light, and am jealous of any competing data, so let's just get that on the table now. Having said that, I intend to have very strong rationales, openly and objectively argued for my data.

What is the rationale for your SME's data about 7.62x54R? I'm skeptical that his BC is better than Sierra's, given that Sierra is actually tested, has a denser lead core that sheds velocity slower, and has a secant ogive. Got a link to his data?

I'm gonna go with 2550 fps for the 112gr 65G @ 0.523 BC (this is a conservative BC because that's the 2400 fps BC).

ARRRRRGH! I just spent two hours composing a reply, only to lose it all because of the forum's %&@#ing auto-log out!

Okay, abbreviated version.

SME apparently does a lot of official government testing of military small arms ammo, and is held in high regard on Tony's MG&A forum.

Links to SME's 7.62x54R LPS data:

* BC http://forums.delphiforums.com/autogun/m...msg=5922.7
* MV http://forums.delphiforums.com/autogun/m...msg=5922.9

Did a lot of searching, but was unable to find any manufacturer listing of .311" bullet of required weight and shape. Closest fit is Nosler .308" 150gr E-Tip, a solid copper bullet (much closer in material density to steel-core LPS) with boattail and tangent ogive. BC = 0.469, so I still think 0.406 is reasonable for the LPS.

Am skeptical that BC of a 110-112gr, 6.5mm military ball projectile will get above 0.480 (if even that high), but I nevertheless look forward to seeing your ballistic comparison.