The J-27 is designed to transport dangerous munitions and missiles from a rear supply area to BattleMechs and infantry units in the field.   It was the backbone of the Star League's ordnance service prior to the League's collapse, and many of these transports are still active in the Successor States.
         Designed for rear-area operations, the J-27 has thin armor and so makes an explosive target.   The munitions it carries are not protected in any way, exposing the transport to danger every time the vehicle nears the combat zone.   Extreme heat can also pose a grave threat to crew members of the J-27.

         Even though the J-27 plays a crucial role in combat by providing front-line troops with ammunition, such duty is usually considered punishment rather than a privilege.  
         The J-27 can transport three tons of munitions in its front, tracked cab.   Its wheeled trailer can carry another eight tons of ammunition.   The front cab usually supports long-range missile reloads, but the missile rack can be removed in minutes to take on other munitions.
         For the most part, the personnel of J-27s are losers from the infantry.   Some units, especially those of the Draconis Combine, are considered penal units.   Military convicts are offered the choice between a firing squad and duty on the J-27.   The majority choose the firing squad.   It takes two people to drive the slow transport; the third crewmember is in charge of securing the munitions and manning the single SperryBrowning machine gun mounted over the cab.   The mount is designed so that it cannot fire low enough to hit the supplies in the cab or trailer.
         One major drawback of the J-27 transport is that the trailer can only be detached from the cab manually.   When a J-27 comes under fire, the load checker must detach the trailer to make the vehicle a smaller target.   Unfortunately, in most cases he must crawl across the cab's cargo and down the back of the cab to disengage the trailer while the vehicle is rumbling across the countryside and taking enemy fire.

         During the initial battles for Les Halles in 2880, House Liao used this vehicle extensively to maintain their control of the planet.   When House Marik finally drove the Liao army off the world Marik forces managed to capture a large number of J-27 transports intact.   Captured Liao J-27s have seen combat all the way to the Lyran world of Loric.
         House Kurita's raid on the world of Huan succeeded at least partly because of their aerospace fighter attack on Davion munitions supplies in the Nestling Lowlands.   Kurita fighters strafed the convoys of J-27s that were trying to re-arm elements of House Davion's Royal Militia, blowing the convoys to bits along with their cargo. The Royal Militia never received its ammunition, and the Kurita attackers crushed the Davion forces in four days.
         Penal units were first used by the Free Worlds League, and the policy of using military convicts as J-27 crew members quickly spread to most of the other Houses.   House Steiner and House Davion do not follow this practice, feeling that ammunition handlers need better motivation than facing certain death.   Of course, if a soldier from one of these Houses gets out of line, he may find himself on temporary J-27 duty.
         One such penal unit is Liao's 125th Deadmen Ordnance Carriers.   During battles for the planet New Hessen against Davion forces, the 125th Deadmen carried well over a thousand times their own weight in munitions just to keep the Liao forces in a   defensible position.   At one point, two Deadmen convoys came under attack by Davion 'Mechs.   In the heat of battle, several Deadmen took down their long-range missile racks and set up a makeshift firing station.   The convoy battled for several hours against the Davion troops, and eventually drove them from the battlefield.   For their efforts, several members of the Deadmen were promoted to other duty, but some volunteered to remain with their J-27s.