In regards to muzzle flash on .50bmg rifles...
Awhile ago a bunch of friends and I went to one of their farms for a day of shooting. I knew we'd be there for awhile, and I was anxious to see, what I assumed to be, a significant amount of flash from my AR-50 as it would be the first time shooting it not in broad daylight.
It was an overcast day and we were shooting a well into twilight. My AR-15, as to be expected, was displaying its considerable muzzle flash. It was getting dark, so time to get back onto the .50. Nothing. Not a thing. I was fully expecting to see a huge fireball extending forward and to the rear around the shooter due to the muzzle brake. Nothing. If there was a flash to be seen, it was dim enough to see it.
Hmmm...could the muzzle brake be pulling double duty?