Complex sentence: There has been speculation that the liner in the AT4's HEAT warhead is constructed of a special aluminum alloy, and others have stated it is primarily a copper liner with a secondary liner of aluminum bonded to the back of the copper liner.
Split into simpler sentences: There has been speculation that the liner in the AT4's HEAT warhead is constructed of a special aluminum alloy. Others have stated it is primarily a copper liner with a secondary liner of aluminum bonded to the back of the copper liner.