Was at the range yesterday comparing three 7.62 AK's.

One is a WASR, and the two, Romanian AKs built on a kit from AoA with Nitride barrel, pre head spaced and drilled gas port. All standard 16" barrels.

The builds throw a huge fireball with the muzzle nut, an angle brake, and even an AMD65 brake. Only the shape of the flash changes (from a ball to a cone).

The WASR emits no real muzzle flash at all regardless of muzzle device.  The only flash we could see was INSIDE the AMD65 brake, but not outside.

We tried swapping ammo, no change.

My first reaction was "gas port!" but then the more I thought about it the less sense that actually made.

Any idea why two rifles emit a huge fireball and the other doesn't?

Thanks

My best guess is that the chrome lined barrel of the WASR is causing the powder to nearly completely combust while the nitrided barrels do not allow the chemical reaction that prevents the nearly complete combustion of the powder... Maybe?

I figured it might have to do with bore diameter... maybe one is slightly smaller, building more pressure and allowing complete burn of the powder.

Perhaps the chrome lining makes the bore slightly tighter.