David, I am understand what you have a very small information about Soviet penal battalions of WWII. Most of available on English language information like a "Enemy at the Gate" and Antony Beevor's books use old-fashioned and tendentious information from Cold-war era stories and propaganda. Now question of penal units of Red Army is more investigate through archive view, available many memories of people who have been in penal units and people who have been of commanders in penal units.
Only officers condemn to penal battalions. Privates and NCO condemn to penal companies. All soldiers of penal units has individual weapons (in early period of war it was rifles, but in late period they has rifles, submachine guns, machine guns, beute panzerfaust an other infantry weapon). Penal units often has a exercise before use in action, because many peoples from various army branches (artillerymen, chemical units, rear service, aviation and other) haven't infantry skills. For penal units selected best infantry officers and this commanders participate in attacks with whole unit. Most time penal units situated in rear and typical using was a leading of infantry attack in big offensive after artillery fire.
Yes, loss of penal units was a pretty hight (in 3-6 time more than loss of common units), but showed soldiers with cudgels on the slaughter is the wrong.
It is very ruefully what Western people haven't objective information about WWII on Russian front. But I can notice what many Russians also situated in captivity of myths (and about penal units also).