Requirements for Replacement of Currently Issued 5.56 M-855 and 7.62 M-80.

[JASmith]

...If ammo weight is a requirement, you must state your requirements in priority.

Concur -- we should plan on setting points or weighting factors for each requirement. As indicated earlier, we need to be absolutely sure that a threshold can be met, else, we guarantee failure.

If recoil forces are a requirement, state the requirement in terms of energy and then prioritize that requirement too.

Tony, there was a huge amount of discussion on this in MG&A. Is there a way you could summarize and propose a maximum acceptable recoil energy (the threshold), and a "nice to have" level (the objective)? I believe we would either need to specify the rifle mass or allow the rifle mass to be part of the trade space.

...state 'same vertex as M-80, same Ke at 1K meters' without even being able to state why 1K is required...

At the risk of putting words in Tony's mouth (keyboard??), the MG&A forum indicates that the 1000 meter range is for GPMG applications. The 7.62 M80 is the existing standard, so equaling or improving its performance is viewed as necessary.

On the political side, I tend to concur that meeting or bettering 7.6X51 performance is necessary.

Your comments are exactly right from the technical side. But we need to find testable [I]and[I] achievable standards,

What small arms optic allows anyone to see and ID an enemy that far?

Concur -- many of the requirements for the standard rifle/carbine are not yet well defined. This is one of the reasons I expect the list of requirements to grow. Projected ROE and sighting systems for the average soldier will impact them, and, may possibly need to be explicitly called out.

Here is a requirement for you guys. Give me a 15 inch ordinate at 500 meters. Issued optics allow a guy to positively ID someone that far (most of the time) but not farther. A 15 inch ordinate means that in most wind conditions a two minute hold ought to offer a better than even chance of a hit without having to spend days trying to teach someone to dope winds which most won't do when under threat.

I assume the 15 inch ordinate (vertex?) is based on a center hold on a 30-inch torso. We need to be careful to not ask for the impossible. Not even the CorBon load for the 123 gr Scenar in a 24-inch barrel chambered for the .260 Remington will get that (the range is 416 meters per JBM calc).

If one assumes a center hold on the torso but allows hits lower, then the .260 Rem gets a "max point blank range" of 490 meters.

The 'old' M855 with a muzzle velocity of 2790 ft/sec (14.4 in bbl) gets a max range of 383 meter for a 15" max ordinate and 446 meters for bullet flight 15" above and 15" below the sight line.

So, one would need to think about how to attain a useful range of 500 meters through a combination of raw exterior ballistics and sighting systems.

How much should we bring optics and sighting systems into the requirements? How far can we go by simply discussing the ROE, optics, etc. as background in the overall document and as a more detailed discussion for the relevant requirement?

Give me accuracy potential from rifle / sighting system / and ammo of about 3 inches mean radius at 500 meters. That is a little over two minutes and ought to be possible in terms of production without costing trillions of dollars.

For most of us, this would be a no-brainer. Can you expand to show the significance 3" mean radius when the torso is about 18" across?

Let a Joe be able to shoot a bullet through the side door of a car with the window rolled down and penetrate at least fifteen inches of ballistic jel representing the width of an adult male. And this happens at 200 meters required, 500 desired. Same for shots through the windshield -- 200 required, 500 desired.

Good start -- details need to be worked.

If I recall correctly, items #2 & #5 addressed this last point.

I'll expand my thoughts a little in my next post - this one is a tad long...