I guess that revolvers are no longer in consideration, but I think that one might be a fine solution. A rugged Ruger GP 100 in .357 would be a reasonable choice. Or a single or double action in .45 Colt or .45 ACP. A revolver could use metal-jacketed bullets with effective flat noses and not have any issues with unreliable feeding. In double action, speedloaders are not an unreasonable way to reload. I will not be surprised if the Army does not take any notice of these suggestions however, as they never requested my opinion during the 21 years I was a soldier.