Hi, I thought I'd share my grinding route where you can get 9
helmets every 10-15 seconds consistently. So every 10 runs = 90 helmets. Note: I did this, and you should too, AFTER finishing the game, all Übercommander missions, and getting all collectables so I had picked up a good amount of helmets. Therefore grinding this only took about 30-40 minutes.
1. Load up the Penthouse district (in Manhattan) and make a save.
2. 5 or so steps in front of you on a shelf are are 2 (2/9) helmets, turn left and jump down past the stairs, next to the stairs on a green bag is helmet 3 (3/9). Just ahead of this bag on a crate are helmets 4 and 5 (5/9). Keep going forward some more to the back wall and you'll find 6 and 7 (7/9). Turn left and go past the tables and where the Commander is, turn right into the back "alcove" area and next to a chair are the last helmets (9/9).
3. Reload save and repeat.
For those that like videos, here you go. I first slowly show you the helmet locations then show how fast this can be done. Also, the load times are very short in this district (I'm sure on the Xbox One X the loading is almost non existent) so each run is very quick. Hope this helps!
Sorry, this Game Clip has been removed