.... Also does the AP ammo increase suppression like the MG34 and 42 AP ammo does? Because that'd be very much helpful vs blobs.
The AP rounds of the weapon you have mentioned all increase damage and penetration and there is little reason that they should also increase suppression (unless damage is somehow connected...)
On topic: I know the 50cal seems really good sometimes when playing against it, but using it I feel like if it doesn't suppress in 1 burst the CD just takes forever and you end up getting flanked. Had a game last night where my gunner kept getting sniped by the Ober+pfusi blob of death and my 50s could just not handle it. But USF would be a lot easier to balance if they didn't get free squads.
1) Having the gunner targeted is in way "bad luck" since the other crew member should have priority. Probably only the gunner was in range...
2) Note that vet 1 increases the suppression of the weapon.