u/Bommes

Since someone posed a question about whether the Death Shadow Mask provides any protection under the helmet and no one had a clear answer I decided to test it with a 20% enchanted mask.

In all the tests the mask protected at least 1x Igolnik or M995, whether you're just wearing the mask or wearing an Altyn or Fast MT face shield in front of it. It reduces the damage by exactly the amount you would think it does (20%). Wearing a face shield or Altyn in front of the mask reduces the durability wear it takes from taking a shot, which often allows it to keep the enchant for a second shot.

Hope that clears it up. It always protects from the shot like it should in the test I did.