I've noticed with both AA halftracks is that it tends to destroy the cover in front of the unit first before it starts to do damage to the squads behind it. Until every obstacle is destroyed in between the halftrack and squad then it does a ton of damage. Also 2 ratten hits or 1 panzershreck and a surprise puma can take it out before it has time to deal with the mg-34.
I'm gonna try 4 rifle into quick grenades but I've found volks grenades so much better than rifle grenades. I'll like to see the stats but maybe it's just me trippin'.