New 350 a little confused with "power"

I thought of somehow filling in the breech seal pocket to bring the seal up but noticed it was machined uneven as well as to deep. I am going to send it in as much as I don't want to. Art from RWS said they would replace the entire barrel and breech assembly. I already made a plastic disc to bring it up along with two foil washers. I got it working but the velocity deviations were as wide as 70 fps with some shots so I gave up. Thanks for the info though ed.