Part II of "Requirements for replacements of currently issued 5.56 M-855 and 7.62 M-8

[stanc]

The practical test I would like to see is an apples-to-apples comparison of optimized loadings (not necessarily peak velocity, but loadings pressure-approved in all temperature extremes) in identical barrel lengths using similar projectiles on identical target test mediums.

5.56N = 77gr Sierra MatchKing (Mk262)
6.5G = 123gr SMK
7.62N = 175gr SMK (M118LR)

5.56N = 62gr T3
6.5G = 110gr T3
7.62N = 147gr T3

I realize it's kind of jumping the gun to just ad hoc test something without thinking through what it is we really want...

John, I don't consider it at all jumping the gun. IMO, there is enough published info on the testing done by the US Army (and the FBI), to do more than ad hoc tests.

...but with this I'd like to establish a baseline to have some data on where we're at with state-of-the-art, but off-the-shelf technology.

AA has 6.5mm 110gr T3 bullets? Excellent!

And I wholeheartedly agree with the desire for test data. IIRC, a "board curmudgeon" on the old forum had been pleading for such tests for several years...

P.S. It also occurs to me that Barnes has an extensive TTSX line of bullets that should include the three calibers mentioned above, for an apples-to-apples comparison of the relative performance of those projectiles.

Not sure if TTSX would yield much useful info beyond relative performance of that particular (non-military) type bullet. FWIW, relative performance could also be tested with a number of other hunting bullets.

However, the SMK and T3 I fully agree with, since those types are used by the military. Also, 5.56mm 70gr and 6.5mm 120gr TSX in 10.5" barrel CQBR, used by SOCOM.

Additionally, since Tony thinks the UK and Europe would require FMJ, I'd add the Norma 6.5mm 120gr FMJ vs 7.62mm M80 FMJ, 5.56mm lead-core 62gr FMJ and 5.56mm M855. I'd much prefer the Wolf 6.5mm 110gr FMJ over the Norma bullet, but you know how that story goes...

P.S. Regarding the UK/European requirement for a non-deforming, non-fragmenting FMJ, the Barnes 6.5mm 110gr solid might be a viable surrogate for test purposes.