Ah the Drill LAW.
In the name of Training realism someone decided that it would be a good idea to require exercising Infanteers to carry LAWs as if they were expecting Tank Action!. Obviously carrying around dirty great big HEAT armed rockets is dangerous so instead it was decided to use Drill or inert LAWs instead.
Now here's the good bit whilst the banger-exploding-whoosh-BOOM bit is bad, the really heavy, pain in the tits bit is consider character building and should be maintained. Hence the Drill LAW is filled with concrete - for realism see.
Now carrying the Drill LAW is never good however successive generations of Infanteers have learned a very important lesson. At the first opportunity get hold of a six foot picket and sledgehammer (defence ex is a winner) use the picket and hammer to drive out the concrete (Best done at night when digging in, it takes ages but it is worth it). If possible you'll want to keep the now MkII Drill LAW under your bed and guard it with you life.