Sorry, The op rod/piston that screws into the bolt carrier is wobbly. Not the cylinder. Seems like it should be OK, but I may disassemble it and see if it can be inserted m ore and if this will affect it at all. Will have to see how it aligns with the exhaust ports. IF you are uncertain what I am talking about due to my lack of appropriate terminology, it is the last picture I posted. The bolt carrier has a piston that screws into it followed by a pin to keep it from rotating out. That is slightly wobbly. Any adjustments to be made with regard to that piece?

Yes, 308 gun. I have shot a couple different mags, but I can work with it again to see if there is an issue with the mags. I have 11 in total, I think, so I can try to run a few through each when I get the chance. Hopefully in early February I can take all my projects to the range to infuriate me all at once.

The striker return spring does not appear to be damaged. Any idea on specs of springs I might need if I wanted to replace them?

I can try to set the gas on 4 and see what happens, but what is the risk of using the gun on 4 all the time? Am I inviting failure and breakage given that this is not an original gun? Will it be more likely to destroy parts given that the pieces are essentially fit to work instead of their original intention?