Trade that M-16 for an M-1, or a BAR, and you could do well with WWII type weapons.
My basic idea was to have 3 men on each fire team with rapid-fire, solidly reliable weapons for close work (AKs), and one man with a solidly reliable long-range weapon (M-14).
I could be wrong, but I doubt it in this case.
1. Why not M-4's in .223 for close, and M-14's for heavy cover and distance? In Death in the A Shau Valley, Larry Chambers recalled that small trees that provided cover against M-16's and AK's, were only concealment in front of an M-14.
2. Someone posted up extraction problems with the .308/7.62x51 round. Were they worse than the M-16's?
3. What about simply carrying stocks of both M-4's and M-14's in the armory, and drawing weapons according to the mission? M-14's would make a lot more sense in Afghanistan and SW Asia generally than either M-16's or M-4's. The M-16 was designed as a jungle gun, and both it and the M-4 ought to take a back seat in other scenarios, don't you think?
4. The comment posted above about shotguns sounds appropriate. Military police used to carry fully-automatic 12-gauges, I don't know their designation but I hefted one at a gun show once (displayed by a Class III dealer), and it must have weighed 20 lbs, empty. Dragunov makes the Saiga, a semiauto shotgun with a Kalashnikov action and a detachable box magazine. There are two possibilities, besides the Benelli Super 90.
5. Economy plays a part here, too. You don't want to mass-waste potential militia weapons that ought to remain in armory, by obsoleting and ending support of the caliber. Which means dancing with the one what brung ya, as far as the rounds are concerned, unless you're willing to mass-convert and rechamber lots of existing stock (.30-06 to 7.62 NATO, e.g.). That drives the cost up and creates political problems you don't need.
I pulled a gig at a Naval Inactive Ship Facility (NAVINACSHIPFAC) in Orange, Texas, for a few months once, and what I saw aboard decommissioned ships being readied to be towed out and expended as targets would make you gag. The waste -- the blind, dumb-assed, criminal waste -- was just staggering. Everything from machine tools to old Underwood typewriters (this was 1971) to Marine hammock covers to ship's running lights, peloruses, binnacles, Sperry gyros, 40-mm mounts and barrels (the ARVN would have liked to have had those, if not our guys!), naval arty in profusion with barrels cut round and optics smashed with bull screwdrivers driven through them, 40-pound engine wrenches, tiny ball-bearing rings still in cosmoline in their wax-paper wrappers, SK cages strewn with stuff. Jesus, it'd make you weep -- and we paid for all this stuff. Dick Nixon was letting his SecNav strike 500-foot, 36-knot hulls sitting at piers while the Navy shoveled gigabucks out to Litton Industries for new-build destroyer-escorts that couldn't do over 29 knots and couldn't defend themselves.
Gives you a certain sardonic sense of what "policy" is all about.
At least we managed to salvage the CO2 extinguishers (some officer up in Little Creek whistled them up -- seems he was short of extinguishers, and we just bailed him out of a procurement pinch, we heard). I assume someone got the mint-condition boat motor we found aboard one old DE, but I'm pretty sure most of the wire rope went to waste. I heard the gas masks we sent the Naval Reserve training centers didn't last long, they dry-rotted pretty quickly once they came out of dehumidification; but the fire hose, probably stood up to city water pressures okay (it was designed to stand up to 400 psi) for training. The Gator Navy got most of the brass fire-hose nozzles we found, and damn, were there a lot of them!
But the stuff that was aboard many of those old ships went to the bottom of the Gulf of Mexico. The rest wound up going to the shipbreakers. Totally squandered.
There are firearms manufacturers that would slaver at the thought of being able to replace all or most of our small-arms armory, but do we really want to do that, if it's paid for and it works? Sure, some turnover is inevitable -- but when the President came into office passing out orders to hold the line on procurement, when the budget-writers in both parties are so eager to stiff procurement, do you really think you can afford a hickey like this? Or would you rather scale back the request to something more modest......and then see about filling depleted ammo stocks? You could do that if you stuck to a triad of the M-4, the M-14 redux, and M-16's in rear-area duty and reserve.