• Long range performance vs. short?
• Penetration vs. energy dump?
• Performance vs. body armor? What kinds of body armor?
• Optimized for which barrel length?
• Accuracy or compactness?
1) – Moisture absorption. The porous material is a no-no here. Even if the propellant is totally non-absorbent moisture will be trapped in the cell structure, producing erratic performance. It would also increase the bulk of the ammunition.
2) -- Vulnerability to ignition in bulk. It is a caseless propellant block, no way around it. But they have gotten it to the point there is no explosion problem unless very confined.
3) – Vulnerability to damage. The propellant is brittle. I know you specified structural integrity, but strength and deflagrate materials fon’t seem to go together. In addition you specify putting it behind the bullet. The increase length to diameter ratio makes it more vulnerable to breakage.
4) – Breach seal requirements. Cased ammo provides a disposable gasket seal, a means of extracting duds, and fixed head spacing. Caseless does not, requiring an entirely new design. Current designs seem to favor swinging or rotary designs with pressure activated seals, which are poorly suited for a longer round like you propose.
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