Pure argon is a pain with mig.
Argoshield has oxygen and carbon dioxide??? In it.
These serve 2 purposes.
One is to create a better arc transition so a smoother weld, but also more heat.
So with pure Argo you'll find you'll always have a rough, tall weld.
I tried playing with argon as I had the bottle with my tig welder..
It's a pita and just but the bullet and got argosheild