Little J wrote:referring to the 6.8 specifically
He is referring to test results with the new round... and can't wait (until next summer) to see how the manufacturers will have handled "any problems"
- he also acknowledges that the two new weapons will be more expensive and will only be distributed to front-line combat units
Tony Williams summarised already in 2010 the problems with the direction the US Army had until the "u-turn":
5.56mm for urban fighting, 7.62mm for open terrain?
PROBLEMS:
1.Combat ranges may change rapidly
2.Mixed calibres in a squad reduces firepower
3.Doesn’t help 5.56mm effectiveness & barrier penetration
4.Doesn’t reduce weight & recoil of 7.62mm ammunition
So, in that same order
- it is not the velocity at the muzzle that matters (exc. for recoil
) but the BULLET ENERGY LOSS with range
- one calibre at squad level ( at the time, in 2010, 6.5 was the recommendation. Now it seems that 6.8 has been settled on)
- the advances in body armour (since) seem to have lifted the priority for (such) penetration... without going "Russian" with steel-tipped becoming "standard"
- as for ammo weight, the best (for weight) seems to have been the enemy of "good enough" and even here we may see a change of direction
"SIG Sauer also displayed their new hybrid ammunition, a three-piece metallic, not polymer design, with a brass body and what appears to be an alloy base. Solider Systems report that this new ammunition offers a 20% reduction in weight – this was a stipulation of the 2017 SOCOM Medium Machine Gun solicitation. The hybrid ammunition was displayed in a number of calibres ...
Of course this is only a SIG solution - has not been selected yet - but more radical attempts seem to have gone nowhere, over quite a long period of trying.
Google seems to behind times as my simple question "weight of 6.8 mm XM1186 round vs 7.62 m80" did not return an answer.
- may be the weight (nor velocity) has been released yet?
In January this year Gen Milley was talking in generic terms
" reach out at much greater ranges than currently exist, with much greater impact and lethality, and with much greater accuracy. I don’t want to go into too many of the details on it, but it has to do with the type of ammunition, the chamber pressure of the rifle, and the optics that are being used on the rifle.”
... and the speculation (then) got it slightly wrong, as e.g. in
"Military.com posits that the system Milley was talking about could be Textron Systems’ new Intermediate Case-Telescoped Carbine chambered in
6.5mm. The ammo weighs 35 percent less and is 30 percent more lethal
than 7.62mmx51mm ammo and is a marked improvement over the M4’s 5.56mm ammo"
so, even though the comparison is not quite the same, the 20% reduction by way manufacturing hybrid ammo is not factored in
To me this explains why the weapon prototype request had none of the normal "must weigh less than" or be "no longer than" as it is the system weight (was it with 255 rounds carried?), and there are tech challenges to be mastered... might add weight. But the leeway offered by the above approximated 35% and 20%... make the sum total , as who at this point has the detail for all the permutations of alternatives,40% for now
. That margin is there, some of it to be used up at the total system level, for winning the competition.