help with MIG sputtering

I have a new-to-me Lincoln 250. At higher voltage/wire feed setting for thicker metals I can get a good, consistent bead. At lower settings for thinner material, there is a lot of sputtering, sometimes a pop and loss of arc...occasionally with the wire "sticking" to the tip, then jumping out.

I am using the recommended voltage/feed settings as indicated on the chart posted inside the unit. (I've also experimented with tweaking those settings and practicing.)

My gas (75argon/25CO2) is new, the regulator/hose system has been checked, and the gun is new...so I think that the shield is ok.

MY guess is it could be the pressure screw on the wire feed...but I don't know if I should increase or decrease pressure? (I've tried a little of both...but I've not gotten a result that is reliable enough to tell me this is the solution.)

Ideas?

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look at the drive rollers with a magnifying glass.

if they look worn, that could be the issue.

first, see how much thumb and finger pressure it takes to stop the wire feed.

pinch the wire and pull the trigger. it should take a good bit of squeezing to stop the wire feed.

also, you said the gun is new, but what about the liner?

if you are not sure about the liner, they are pretty cheap so replacing it is an option too.

i suspect the drive rollers and slipping.

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