I haven't actually played with it, but I wonder if the Bang plugin made for muzzle flashes would work? It's lets you do custom shapes. If you can set it so the flames don't flash for just 1 frame it might work? The minigun example they show here looks close if it wasn't flashing: Â
https://aescripts.com/bang/
Though, looking at the classic Top Gun reference, I'd probably try to just build this with some layers of fractal noise:
Thinking out loud,
 - N