Muzzleflashes unrealistic?

[ChrisDNT]

Muzzleflashes depend very much of each peculiar arm.

For instance, the nose cannons of the F-5 E/F have about no visible muzzleflash, but the Aden cannons of the Hunter or the Hawk had a very big muzzleflash (not important, as the Aden was always fitted under the belly of the aircrafts).

That means it would be totally illogical to conceive a nose cannon or machine gun which would provide a heavy muzzleflash, which would end in the pilot not seeing where he aims.