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

[JASmith]

This next step addresses terminal performance (items #2 & #5 in Tony & Gene's list) --

The question of terminal performance is the emotional driver that leads us to where we are now. On the technical side, Tony points out that recoil is critical, Gene improving hit probability, and so on.

Gene suggests that:

LR1955]
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.

We need to expand this and to ask if other barrier perforation thresholds are needed. Cinder blocks, unfilled, or filled, come to mind...

Starting with the door-frame, here's an extract from an earlier post that illustrates some of the complications:

(From Post #21) ...An example of unintentional violation of the simplicity rule occurs when one specifies "X mm penetration in ballistic gel after perforating a truck door frame." The hiccup occurs when you actually use the door frame in developmental testing, one can be led astray by the inevitable interaction with the things that are inside the door frame.

So the apparently obvious solution is to replace the door frame with sheets of door frame material with the appropriate air gap. This makes an incomplete statement, because one needs to also specify the frequency the bullet is likely to encounter something besides air in the space between the exterior and interior sheets. We likely need to make this statement rather than requiring that the bullet pass through the braces, fasteners, door latches, window cranks and gears, etc. The added requirement would likely make the bullet way too big for normal infantry applications.

Next, one needs to state the obliquity at which the bullet must be able to attain the specified penetration into the ballistic gel, or engine block, etc. behind the "door frame." Oops! the increased angle means that the interior stuff gets hit more often. How often?

Aw heck, the off-angle impact makes my bullet start to tumble and the increased travel time makes the bullet turn enough that it won't penetrate the second sheet.

And so on......

My caution is that the transition from truck-stopping, armored bad guy incapacitation, etc. to testable targets is not a trivial step.

The door frame and windshield scenario is a common one. Let's check on existing requirements practice in this area.

Does anyone have insight into what RARDE, Picattiny, etc. are using?