Maybe demolitions can use a mortar launcher? He'd have to set it down to fire(Of course, damn things weigh at least a couple hundred pounds :/), but he would have access to various types of shells besides HE, like Anti-vehicle, smoke, and hell maybe even Agent Orange(Then again, we all know how the m119 howitzer's Toxic shells annoy the hell out of everyone -_-).
He could also use a recoiless rifle that would be more accurate and precise, yet lack the true explosive power of the 'zook, thereby making it's use against groups of soldiers somewhat less efficient. Or at the very least give the 'zook a tripod/bipod for steadier accuracy.
There's always grenade launchers to use (Albeit a little generic methinks)