[SeeSac]

Not only is the contrail spiralling [and I don’t mean tight ringlets] unlike a missile, but it starts off wide and rapidly narrows. Missile contrails don’t normally do that, do they?

[Arthur Wildfire! March]

Commercial jets are fairly uniform. Are all the world’s missiles uniform?

[TigersEye]

Not only is the contrail spiralling [and I don’t mean tight ringlets] unlike a missile, but it starts off wide and rapidly narrows. Missile contrails don’t normally do that, do they?

Yes, they sure do. Both corkscrew plumes and wide plumes at the base are two of the easiest things to find in videos of missiles.

Delta 2 STSS Demo Rocket Launch - SpaceflightNews.net

A great example of corkscrewing of the plume begins about 1:25 into the video. The differences in plume thickness and consistency can clearly be seen later.