I would check the gas system including barrel ports for carbon build up and clean and lube all sliding parts with Break Free CLP. I would also clean the chamber of the gun. A third suggestion is to switch from Green Dot to E3 powder, faster burning and cleaner.
Does it cycle factory loads?
Green Dot is a really poor powder choice for 1oz, esp in an auto. You didn't say what primer/wad you're using, but most of the loads I'm seeing on the Alliant website are on the hairy edge of running any auto, and there are many that won't. You could be under 7k PSI depending.
Switch to something toward the faster end of the burn chart and your problems will go away.
I forgot one thing, does your reloading press resize the hull including the steel base, and it adjustable like the MEC collet resizer? Since they chamber and fire, this is not likely to be the problem, just another thing to consider.
How much are you sizing your gun clubs? Could be you need to size them a bit more for your auto. Also as one other has said green dot in 1 oz loads pressures are pretty low for an auto. Try some red dot to bring your pressures up. What other components goes into your shells?