Today's HK .45, with infared aiming and suppressor, is what the military wanted after the Nam tunnel's. They needed at most 500 of them, so in typical military style, they bought 5000, for $5000 apiece, at a time when that was like twice as much money as today. A real coup for HK at the time. the silenced .44 ammo developed about the same power as a .22 rimfire rifle, IIRC. very feeble, because the cartridge had to contain the piston that drove the bullet. If the gases were left free to exit the revolver at the cylinder gap, the noise would still be horrendous in a small diameter tunnel.