I can't really tell by the photo, but i think it could potentially be Belgian M51
( Airforce issue- hence the colour of the inner and straps)
A lot of these european M1 style helmets are Austrian manfacturered. Most of the time Ulbrichts Witwe made em!!
Could you post a close up of the bale fixings, and the rear seam ??
Hope this helps with your ID.