So I finally got it installed. I only bought 2000 grit at first and that was imposssible. I kept applying oil and made my patch swell a lot. Had to recut it to fit, bought some 400 grit sandpaper and now it's finally installed. There is no barrel intrusion on inside or outside of barrel and the hop up is engaging normally.
Going to have to go to my old mans place to do tests, but it looks pretty good. Wish they gave a little bigger patch for how much they cost and for people who screw up like me.
! On mobile; sorry for any spelling mistakes or autocorrects!