Might I suggest that you use a knurled feed roll with a pressure roll on top.We have done extensive tests with both solid wire and cored wire,the knurned roll comes out best
I've got one of them, They are a good simple solid machineI've finally sussed it guys, its an Esab LAG 400.
Matches exactly, though possibly the miller equivalent given it used to be blue not yellow. Bit peeved that I have painted it Red now.