An Army M2 Bradley Infantry Fighting Vehicle in Iraq.

Massive government documents typically hide some gold nuggets of information. In today’s report from the Pentagon’s independent Director of Operational Test & Evaluation, a famously tough grader known as DOT&E, there’s one detail that is going to make defense contractor BAE Systems very happy:

“Results from the third underbody blast test also demonstrate that the Armored Multi-purpose Vehicle survivability requirement is achievable with a Bradley-like platform.”

Why should BAE care? Well, because BAE builds the M2 Bradley, a tank-like troop carrier, and because they’re entering a Bradley variant in the Armored Multi-Purpose Vehicle competition. With the much heavier, more powerful, and more expensive Ground Combat Vehicle (GCV) apparently in programmatic limbo due to budget cuts, the humble AMPV is the biggest game left in town for anybody who builds armored vehicles for the US military. That boils down to BAE and its competitor General Dynamics, which is offering a variant of its Stryker vehicle.

Why should anybody else care? The answer has to do with the deadliest single threat to US troops today, the improvised explosive device (aka the IED or just plan “roadside bomb”), and with how the Army can address that threat.

The Bradley looks like a tank — tracks, turret, gun, the works — but it is technically an “infantry fighting vehicle” because it carries half-a-dozen passengers into combat in addition to its three-man crew. The Bradley has been the Army’s frontline troop carrier since the 1980s, but like every other vehicle, it struggled to catch up to the ever-escalating IED threat in Iraq. While the uparmored Humvee and its replacement, the MRAP (Mine Resistant Ambush Protected truck), are the most famous cases, all sorts of other vehicles got extra armor, including the Bradley.

But even that wasn’t always enough. At the height of the surge, when sophisticated Iranian-designed IEDs called “explosively formed projectiles” were punching slugs of molten copper through American armor plate, one young officer told me he had to keep his Bradleys in the back of the column and lead with massive M1 Abrams tanks, because the Bradleys were just too vulnerable.

The Bradley undergoing the “underbody blast test” that DOT&E mentions, however, was partially upgraded to a new standard called “Engineering Change Proposal 1.” ECP1 doesn’t just add extra armor on the outside: It also changes the passenger compartment, especially the flow, and rearranges how ammunition is stored to minimize potential damage to the troops inside.

“The blast test revealed that significant improvements to the Bradley Fighting Vehicle Systems (BFVS) level of force protection and vulnerability are feasible,” DOT&E said. That’s good news for BAE, which wants to keep getting contracts to upgrade the Bradley, and it’s good for the Army, which isn’t going to replace its Bradleys any time soon now that the Ground Combat Vehicle is being put on hold.

Instead of buying Ground Combat Vehicles to replace Bradleys, the Army is now focused on buying Armored Multi-Purpose Vehicles to replace M113s, a lightweight tracked vehicle whose design predates the Vietnam War and which is considered so vulnerable the Army didn’t let them off its bases in Iraq. Back in the 1980s, the Bradley replaced the M113 in the mission of carrying infantry soldiers into combat, but the Army still has thousands of M113 variants serving support roles from armored ambulances to mobile command posts. Those vehicles aren’t just old: In the IED era, when enemies can attack your support forces more easily than your frontline troops, they’re also dangerously vulnerable.

The Army’s aspiration — more a hope than a plan given the current budget crunch — is to buy almost 3,000 AMPVs for $6 billion. BAE has to convince the Army that the Bradley design can be made survivable to have a shot at that contract.

The DOT&E report has some good news for BAE’s rival General Dynamics Land Systems, as well. GDLS builds the Stryker, a eight-wheel-drive armored transport. The Stryker troop carrier’s troubled brother is the Mobile Gun System, a Stryker variant fitted with an almost comically overlarge 105 millimeter gun, the kind of weapon normally reserved for battle tanks twice its size:

A Stryker Mobile Gun System (MGS) fires its 105 mm main gun.

After years of development problems, the Army ultimately bought 142 Mobile Gun Systems and sent MGS to war. As late as 2008, however, the Pentagon issued a report going through the MGS’s flaws. But it’s got better: “The Army has mitigated, by either material fixes or tactics, techniques, and procedures, 22 of 23 deficiencies identified in the 2008 Secretary of Defense report to Congress,” DO&TE wrote. What’s more, “in live fire testing,” an upgraded set of “Stryker Reactive Armor Tiles” (SRAT II) showed it could make MGS and a wide range of other Stryker subtypes more survivable without the expense of totally rebuilding the hull.

That gives the Army a cheaper option to upgrade older Strykers that to rebuild them entirely as “double-V-hull” vehicles. It also makes the MGS a more attractive option for the Army’s light infantry units, which are looking for a new light tank to support foot troops and even be flown in quickly to reinforce paratroopers.

By contrast, the lightest and most nimble part of the military, the Special Operations Forces, got some bad news in DOT&E’s report. SOF wants its own souped-up version of the most mobile type of MRAP truck, the M-ATV (MRAP All Terrain Vehicle), but it’s had problems and recent tests show that ” the most significant deficiencies were not resolved.” While the special ops M-ATV is nimbler and quieter than the standard version, DOT&E says, it’s too hard for the commandoes inside to see out in all directions: The rear windows are too small and the video camera on the remote-controlled rooftop weapon, called CROWS, has too limited a field of view. And if there’s one thing stealthy special operators hate, it’s for someone else to sneak up on them.