Complex sentence: These rifle grenades come in "standard" type, which are propelled by a blank cartridge inserted into the chamber of the rifle; or, "bullet trap" and "shoot through" types, which allow the use of live ammunition.
Split into simpler sentences: These rifle grenades come in "standard" type, which are propelled by a blank cartridge inserted into the chamber of the rifle. Or, "bullet trap" and "shoot through" types, which allow the use live ammunition.