Timactual in the comments on the M8 AGS asks a reasonable question:
“The three man crew could bolt on the additional protection in a couple hours with simple hand tools.”
Why, oh why, am I so skeptical.
Why not bring back the 106 mm. reckless rifle? Mount it on an modified and armored Humvee, like the Germans did with the Marder.
I like the M40 106mm Recoilless Rifle (which has proven popular with Syrian rebels). It’s a nifty weapon. My thoughts on why the Army doesn’t bring it back into service are pure speculation, of course, but I think you’ll see the logic has merit.
First, as to his skepticism about mounting the bolt on armor, it really was pretty easy to do.
As to why you’d want a rifled cannon mounted on a vehicle instead of an M40- the M40 was only capable of defeating armor via its HEAT warhead. It’s low muzzle velocity ruled out using any kinetic penetrator. HEAT warheads offer fantastic penetration for a given size round. The problem is, they can be defeated by a pretty wide variety of simple countermeasures. See the slat armor on US Stryker vehicles deployed in the war zones. Or simply a little vegetation can set off the warhead before it reaches the armor. The 105mm main gun of the M8 can fire existing sabot rounds that are fully capable of defeating tanks up to various T-72 models. And if you’re facing a threat with more advanced armor than that, you’re going to need more than Airborne forces anyway.
As to why the Army doesn’t bring back the M40 to complement the firepower of Infantry Brigade Combat Teams, I suspect it is mostly because, they don’t really need it. IBCTs are fairly generously equipped with the TOW and Javelin missile.
A Javelin is a crapload more expensive per shot than an M40. On the other hand, it is also virtually a one shot/one kill system with greater effective range than an M40. And the Army has so many TOW missiles in the inventory, we can afford to expend them at a pretty brisk rate for years and years to come. Most stocks of US 106mm ammo are expired, and the ammunition in use today overseas is made overseas.
As much as I like the M40, I just don’t think bringing it back would solve any issues that can’t be address by other means. Yeah, you could probably save a little money, but there’s no gain in combat effectiveness, so why bother?