Okay
, maximum runout on the piston is .00035 so, it's small, send it to Columbus Machine, while you're at it it would be good to have them check and set the bends. Jim Swartz, when he quit doing this, sold them his equipment which included a $1,500.00 bend-gauge for the M1 Op-Rod.
Your Gas-Cylinder sounds servicable.
If your gas-screw has a single screwdriver slot it's solid, otherwise it's a poppet-valve type(Slot looks like a big
lipshead). If it's cross-slotted, turn it upside down, put a 1/8th punch into the slot-center and push down onto a hard surface. The face will rise up. There could be grit or carbon stuck in it holding it partially open. Scrub the inside good with a toothbrush and Hoppes'. Then let it soak in Hoppes' for about 1/2 hour and scrap off the face with a penny until the black(Carbon buildup) is gone. Now, you can check the face for a crack. If you find a crack in it let me know, I have some extra servicable screws.I'll send you one.
Barrel-port- Chuck up the bit(#47) in a variable-speed batterydrill or better yet a Dremel or foredom tool and slowly run it into the port, making sure you run it straight in. It sounds like there's a carbon buildup around the hole.
Dave